diff --git a/src/main/java/net/openhft/chronicle/map/VanillaI24I24MultiMap.java b/src/main/java/net/openhft/chronicle/map/VanillaI24I24MultiMap.java
new file mode 100644
index 000000000..cb96fdfde
--- /dev/null
+++ b/src/main/java/net/openhft/chronicle/map/VanillaI24I24MultiMap.java
@@ -0,0 +1,304 @@
+/*
+ * Copyright 2014 Higher Frequency Trading
+ *
+ * http://www.higherfrequencytrading.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.openhft.chronicle.map;
+
+import net.openhft.lang.collection.ATSDirectBitSet;
+import net.openhft.lang.collection.DirectBitSet;
+import net.openhft.lang.io.Bytes;
+import net.openhft.lang.io.DirectStore;
+
+import static net.openhft.lang.Maths.isPowerOf2;
+
+/**
+ * Supports a simple interface for int -> int[] off heap.
+ */
+class VanillaI24I24MultiMap implements MultiMap {
+
+    static final int MAX_CAPACITY = (1 << 24);
+
+    private static final int ENTRY_SIZE = 6;
+    //    private static final int ENTRY_SIZE_SHIFT = 3;
+    private static final int UNSET_KEY = 0;
+    private static final int MASK = 0xFFFFFF;
+    private static final int HASH_INSTEAD_OF_UNSET_KEY = MASK;
+    private static final long UNSET_ENTRY = 0L;
+
+    final DirectBitSet positions;
+    private final int capacity;
+    private final int capacityMask;
+    private final int capacityMod2;
+    private final Bytes bytes;
+
+    private int searchHash = -1;
+    private int searchPos = -1;
+
+    public VanillaI24I24MultiMap(long minCapacity) {
+        capacity = (int) VanillaIntIntMultiMap.multiMapCapacity(minCapacity);
+        capacityMask = capacity - 1;
+        capacityMod2 = indexToPos(capacity - 1);
+        bytes = DirectStore.allocateLazy(indexToPos(capacity)).bytes();
+        positions = newPositions(capacity);
+        clear();
+    }
+
+    public VanillaI24I24MultiMap(Bytes multiMapBytes, Bytes multiMapBitSetBytes) {
+        capacity = (int) Math.min(MAX_CAPACITY, (multiMapBytes.capacity() / ENTRY_SIZE));
+        assert capacity <= MAX_CAPACITY;
+        capacityMask = capacity - 1;
+        capacityMod2 = indexToPos(capacity - 1);
+        this.bytes = multiMapBytes;
+        positions = new ATSDirectBitSet(multiMapBitSetBytes);
+    }
+
+    /**
+     * @param minCapacity as in {@link #VanillaI24I24MultiMap(long)} constructor
+     * @return size of {@link Bytes} to provide to {@link #VanillaI24I24MultiMap(Bytes, Bytes)}
+     * constructor as the first argument
+     */
+    public static long sizeInBytes(long minCapacity) {
+        return indexToPos((int) VanillaIntIntMultiMap.multiMapCapacity(minCapacity));
+    }
+
+    /**
+     * @param minCapacity as in {@link #VanillaI24I24MultiMap(long)} constructor
+     * @return size of {@link Bytes} to provide to {@link #VanillaI24I24MultiMap(Bytes, Bytes)}
+     * constructor as the second argument
+     */
+    public static long sizeOfBitSetInBytes(long minCapacity) {
+        return (int) (Math.max(VanillaIntIntMultiMap.multiMapCapacity(minCapacity), 64L) * 6L + 63) / 64;
+    }
+
+    public static ATSDirectBitSet newPositions(int capacity) {
+        if (!isPowerOf2(capacity))
+            throw new AssertionError("capacity should be a power of 2");
+        // bit set size should be at least 1 native long (in bits)
+        capacity = Math.max(capacity, 64);
+        // no round-up, because capacity is already a power of 2
+        int bitSetSizeInBytes = capacity / 8;
+        return new ATSDirectBitSet(DirectStore.allocateLazy(bitSetSizeInBytes).bytes());
+    }
+
+    private static int indexToPos(int index) {
+        return index * ENTRY_SIZE;
+    }
+
+    private static long maskUnsetKey(long key) {
+        return (key &= MASK) != UNSET_KEY ? key : HASH_INSTEAD_OF_UNSET_KEY;
+    }
+
+    private void checkValueForPut(long value) {
+        assert (value & ~MASK) == 0L : "Value out of range, was " + value;
+        assert positions.isClear(value) : "Shouldn't put existing value";
+    }
+
+    private void checkValueForRemove(long value) {
+        assert (value & ~MASK) == 0L : "Value out of range, was " + value;
+        assert positions.isSet(value) : "Shouldn't remove absent value";
+    }
+
+    private static int key(long entry) {
+        return (int) (entry >>> 24);
+    }
+
+    private static int value(long entry) {
+        return (int) (entry & MASK);
+    }
+
+    private static long entry(long key, long value) {
+        return (key << 24) | (value & MASK);
+    }
+
+    private int pos(int key) {
+        return indexToPos(key & capacityMask);
+    }
+
+    private int step(int pos) {
+        return (pos + ENTRY_SIZE) % capacityMod2;
+    }
+
+    private int stepBack(int pos) {
+        return (pos - ENTRY_SIZE) % capacityMod2;
+    }
+
+    @Override
+    public void put(long key, long value) {
+        key = maskUnsetKey(key);
+        checkValueForPut(value);
+        for (int pos = pos((int) key); ; pos = step(pos)) {
+            long entry = bytes.readInt48(pos);
+            if (entry == UNSET_ENTRY) {
+                bytes.writeInt48(pos, entry(key, value));
+                positions.set(value);
+                return;
+            }
+        }
+    }
+
+    @Override
+    public void remove(long key, long value) {
+        key = maskUnsetKey(key);
+        checkValueForRemove(value);
+        int posToRemove;
+        for (int pos = pos((int) key); ; pos = step(pos)) {
+            long entry = bytes.readInt48(pos);
+            if (key(entry) == key && value(entry) == value) {
+                posToRemove = pos;
+                break;
+            }
+        }
+        positions.clear(value);
+        removePos(posToRemove);
+    }
+
+    @Override
+    public void replace(long key, long oldValue, long newValue) {
+        key = maskUnsetKey(key);
+        checkValueForRemove(oldValue);
+        checkValueForPut(newValue);
+        for (int pos = pos((int) key); ; pos = step(pos)) {
+            long entry = bytes.readInt48(pos);
+            if (key(entry) == key && value(entry) == oldValue) {
+                positions.clear(oldValue);
+                positions.set(newValue);
+                bytes.writeInt48(pos, entry(key, newValue));
+                return;
+            }
+        }
+    }
+
+    private void removePos(int posToRemove) {
+        int posToShift = posToRemove;
+        while (true) {
+            posToShift = step(posToShift);
+            long entryToShift = bytes.readInt48(posToShift);
+            if (entryToShift == UNSET_ENTRY)
+                break;
+            long insertPos = pos(key(entryToShift));
+            // the following condition essentially means circular permutations
+            // of three (r = posToRemove, s = posToShift, i = insertPos)
+            // positions are accepted:
+            // [...i..r...s.] or
+            // [...r..s...i.] or
+            // [...s..i...r.]
+            boolean cond1 = insertPos <= posToRemove;
+            boolean cond2 = posToRemove <= posToShift;
+            if ((cond1 && cond2) ||
+                    // chain wrapped around capacity
+                    (posToShift < insertPos && (cond1 || cond2))) {
+                bytes.writeInt48(posToRemove, entryToShift);
+                posToRemove = posToShift;
+            }
+        }
+        bytes.writeInt48(posToRemove, UNSET_ENTRY);
+    }
+
+    /////////////////////
+    // Stateful methods
+
+    @Override
+    public void startSearch(long key) {
+        key = maskUnsetKey(key);
+        searchPos = pos((int) key);
+        searchHash = (int) key;
+    }
+
+    @Override
+    public long nextPos() {
+        int pos = searchPos;
+        while (true) {
+            long entry = bytes.readInt48(pos);
+            if (entry == UNSET_ENTRY) {
+                searchPos = pos;
+                return -1L;
+            }
+            pos = step(pos);
+            if (key(entry) == searchHash) {
+                searchPos = pos;
+                return value(entry);
+            }
+        }
+    }
+
+    @Override
+    public void removePrevPos() {
+        int prevPos = stepBack(searchPos);
+        long entry = bytes.readInt48(prevPos);
+        positions.clear(value(entry));
+        removePos(prevPos);
+    }
+
+    @Override
+    public void replacePrevPos(long newValue) {
+        checkValueForPut(newValue);
+        long prevPos = stepBack(searchPos);
+        long oldEntry = bytes.readInt48(prevPos);
+        long oldValue = value(oldEntry);
+        positions.clear(oldValue);
+        positions.set(newValue);
+        bytes.writeInt48(prevPos, entry(searchHash, newValue));
+    }
+
+
+    @Override
+    public void putAfterFailedSearch(long value) {
+        checkValueForPut(value);
+        positions.set(value);
+        bytes.writeInt48(searchPos, entry(searchHash, value));
+    }
+
+    public long getSearchHash() {
+        return searchHash;
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder sb = new StringBuilder();
+        sb.append("{ ");
+        for (long i = 0L, pos = 0L; i < capacity; i++, pos += ENTRY_SIZE) {
+            long entry = bytes.readInt48(pos);
+            if (entry != UNSET_ENTRY)
+                sb.append(key(entry)).append('=').append(value(entry)).append(", ");
+        }
+        if (sb.length() > 2) {
+            sb.setLength(sb.length() - 2);
+            return sb.append(" }").toString();
+        }
+        return "{ }";
+    }
+
+    @Override
+    public void forEach(EntryConsumer action) {
+        for (long i = 0L, pos = 0L; i < capacity; i++, pos += ENTRY_SIZE) {
+            long entry = bytes.readInt48(pos);
+            if (entry != UNSET_ENTRY)
+                action.accept(key(entry), value(entry));
+        }
+    }
+
+    @Override
+    public DirectBitSet getPositions() {
+        return positions;
+    }
+
+    @Override
+    public void clear() {
+        positions.clear();
+        bytes.zeroOut();
+    }
+}
diff --git a/src/test/java/net/openhft/chronicle/map/IntIntMultiMapTest.java b/src/test/java/net/openhft/chronicle/map/IntIntMultiMapTest.java
index 18d5c8686..852c339b0 100644
--- a/src/test/java/net/openhft/chronicle/map/IntIntMultiMapTest.java
+++ b/src/test/java/net/openhft/chronicle/map/IntIntMultiMapTest.java
@@ -55,6 +55,7 @@ public class IntIntMultiMapTest {
     public static Collection<Object[]> data() {
         return Arrays.asList(new Object[][]{
                 {VanillaShortShortMultiMap.class},
+                {VanillaI24I24MultiMap.class},
                 {VanillaIntIntMultiMap.class},
         });
     }