diff --git a/.gitignore b/.gitignore
index e52e30e..f6fd755 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 target/
 benchmark/
+Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
index a2416ea..1768220 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,4 +10,5 @@ license = "MIT"
 
 [dependencies]
 libc = "^0.2"
+[dev-dependencies]
 rand = "^0.3.9"
diff --git a/src/hamt.rs b/src/hamt.rs
index c4c4b0b..c51027e 100644
--- a/src/hamt.rs
+++ b/src/hamt.rs
@@ -60,8 +60,7 @@ enum BorrowedNodeRef<'a, K, V, IS, H>
 }
 
 impl<K, V, IS, H> NodeRef<K, V, IS, H>
-    where K: Eq+Send+Sync,
-          V: Send+Sync,
+    where K: Eq,
           IS: ItemStore<K, V>,
           H: Hasher
 {
@@ -183,9 +182,7 @@ enum NodeEntryRef<'a, K, V, IS, H>
 }
 
 impl<'a, K, V, IS, H> NodeEntryRef<'a, K, V, IS, H>
-    where K: Send+Sync,
-          V: Send+Sync,
-          IS: ItemStore<K, V>
+    where IS: ItemStore<K, V>
 {
     // Clones the contents of a NodeEntryRef into a NodeEntryOwned value to be used elsewhere.
     fn clone_out(&self) -> NodeEntryOwned<K, V, IS, H> {
@@ -406,8 +403,7 @@ impl<'a, K, V, IS, H> UnsafeNode<K, V, IS, H>
 
 // impl UnsafeNode (continued)
 impl<K, V, IS, H> UnsafeNode<K, V, IS, H>
-    where K: Eq+Send+Sync+Hash,
-          V: Send+Sync,
+    where K: Eq+Hash,
           IS: ItemStore<K, V>,
           H: Hasher+Default
 {
@@ -1159,8 +1155,7 @@ pub struct HamtMap<K, V, IS=ShareStore<K,V>, H=StdHasher> {
 
 // impl HamtMap
 impl<K, V, IS, H> HamtMap<K, V, IS, H>
-    where K: Eq+Send+Sync+Hash,
-          V: Send+Sync,
+    where K: Eq+Hash,
           IS: ItemStore<K, V>,
           H: Hasher+Default
 {
@@ -1336,8 +1331,7 @@ impl<K, V, IS, H> Clone for HamtMap<K, V, IS, H> {
 
 // Default for HamtMap
 impl<K, V, IS, H> Default for HamtMap<K, V, IS, H>
-    where K: Eq+Send+Sync+Hash,
-          V: Send+Sync,
+    where K: Eq+Hash,
           IS: ItemStore<K, V>,
           H: Hasher+Default
 {
@@ -1347,8 +1341,8 @@ impl<K, V, IS, H> Default for HamtMap<K, V, IS, H>
 }
 
 impl<'a, K, V, IS, H> IntoIterator for &'a HamtMap<K, V, IS, H>
-    where K: Eq+Send+Sync+Hash+'a,
-          V: Send+Sync+'a,
+    where K: Eq+Hash+'a,
+          V: 'a,
           IS: ItemStore<K, V>+'a,
           H: Hasher+Default+'a
 {
@@ -1363,8 +1357,8 @@ impl<'a, K, V, IS, H> IntoIterator for &'a HamtMap<K, V, IS, H>
 
 // Eq for HamtMap
 impl<K, V, IS, H> PartialEq for HamtMap<K, V, IS, H>
-    where K: Eq+Send+Sync+Hash,
-          V: PartialEq+Send+Sync,
+    where K: Eq+Hash,
+          V: PartialEq,
           IS: ItemStore<K, V>,
           H: Hasher+Default
 {
@@ -1397,8 +1391,8 @@ impl<K, V, IS, H> PartialEq for HamtMap<K, V, IS, H>
 
 // Eq for HamtMap
 impl<K, V, IS, H> Eq for HamtMap<K, V, IS, H>
-    where K: Eq+Send+Sync+Hash,
-          V: Eq+Send+Sync,
+    where K: Eq+Hash,
+          V: Eq,
           IS: ItemStore<K, V>,
           H: Hasher+Default
 {
@@ -1407,8 +1401,7 @@ impl<K, V, IS, H> Eq for HamtMap<K, V, IS, H>
 
 // FromIterator
 impl<K, V, IS, H> ::std::iter::FromIterator<(K, V)> for HamtMap<K, V, IS, H>
-    where K: Eq+Send+Sync+Hash,
-          V: Send+Sync,
+    where K: Eq+Hash,
           IS: ItemStore<K, V>,
           H: Hasher+Default
 {
@@ -1467,8 +1460,7 @@ pub struct HamtMapIterator<'a, K, V, IS, H>
 
 impl<'a, K, V, IS, H>
 HamtMapIterator<'a, K, V, IS, H>
-    where K: Eq+Send+Sync,
-          V: Send+Sync,
+    where K: Eq,
           IS: ItemStore<K, V>,
           H: Hasher
 {
@@ -1486,8 +1478,7 @@ HamtMapIterator<'a, K, V, IS, H>
 
 impl<'a, K, V, IS, H>
 Iterator for HamtMapIterator<'a, K, V, IS, H>
-    where K: Eq+Send+Sync,
-          V: Send+Sync,
+    where K: Eq,
           IS: ItemStore<K, V>,
           H: 'a + Hasher
 {
diff --git a/src/item_store.rs b/src/item_store.rs
index dbfee89..3958b3c 100644
--- a/src/item_store.rs
+++ b/src/item_store.rs
@@ -23,7 +23,7 @@ use std::sync::Arc;
 //=-------------------------------------------------------------------------------------------------
 // trait ItemStore
 //=-------------------------------------------------------------------------------------------------
-pub trait ItemStore<K, V>: Clone+Send+Sync {
+pub trait ItemStore<K, V>: Clone {
     fn key<'a>(&'a self) -> &'a K;
     fn val<'a>(&'a self) -> &'a V;
 
@@ -40,7 +40,7 @@ pub struct CopyStore<K, V> {
     val: V
 }
 
-impl<K: Clone+Send+Sync, V: Clone+Send+Sync> ItemStore<K, V> for CopyStore<K, V> {
+impl<K: Clone, V: Clone> ItemStore<K, V> for CopyStore<K, V> {
     fn key<'a>(&'a self) -> &'a K { &self.key }
     fn val<'a>(&'a self) -> &'a V { &self.val }
 
@@ -52,7 +52,7 @@ impl<K: Clone+Send+Sync, V: Clone+Send+Sync> ItemStore<K, V> for CopyStore<K, V>
     }
 }
 
-impl<K: Clone+Send+Sync, V: Clone+Send+Sync> Clone for CopyStore<K, V> {
+impl<K: Clone, V: Clone> Clone for CopyStore<K, V> {
     fn clone(&self) -> CopyStore<K, V> {
         CopyStore {
             key: self.key.clone(),
@@ -61,12 +61,16 @@ impl<K: Clone+Send+Sync, V: Clone+Send+Sync> Clone for CopyStore<K, V> {
     }
 }
 
+unsafe impl <K, V> Send for CopyStore<K, V> where K: Send, V: Send { }
+
+unsafe impl <K, V> Sync for CopyStore<K, V> where K: Sync, V: Sync { }
+
 
 
 //=-------------------------------------------------------------------------------------------------
 // struct ShareStore
 //=-------------------------------------------------------------------------------------------------
-pub struct ShareStore<K, V> {
+pub struct ShareStore<K: Sync + Send, V: Sync+ Send> {
     store: Arc<(K, V)>,
 }
 
@@ -86,3 +90,7 @@ impl<K: Send+Sync, V: Send+Sync> Clone for ShareStore<K, V> {
         }
     }
 }
+
+unsafe impl <K, V> Send for ShareStore<K, V> where K: Send + Sync, V: Send + Sync { }
+
+unsafe impl <K, V> Sync for ShareStore<K, V> where K: Send + Sync, V: Send + Sync { }
diff --git a/src/lib.rs b/src/lib.rs
index a66dbb8..16cb6e1 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -27,7 +27,7 @@
 #![allow(unused_parens)]
 
 extern crate libc;
-
+#[cfg(test)]
 extern crate rand;
 
 pub use hamt::HamtMap;