1/2'' impact socket does not fit 1/2'' impact driver

前兩天在這裏跟風也買了1/2 Chicago Impact wrench, 

也買了

Craftsman Evolv  1/2-Inch Drive, 5-pc. Impact Socket Set, Inch

However the socket does not fit into anvil of the impact wrench.

They both are size 1/2 , what I miss here.

多謝了！