diff --git a/src/lib.rs b/src/lib.rs
index a98186e..99a3d5c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -30,7 +30,7 @@ fn block_bit(x: &u64, d: &u64) -> (u64, u64) {
     (x / d, x % d)
 }
 
-#[derive(PartialEq, Eq)]
+#[derive(PartialEq, Eq, Clone)]
 pub struct BitSet {
     blocks: Storage,
     nbits: usize,