1/2''drive knuring handle, Extension bar *alloy *Chrome Plated *3'',5'',10'' extention bar *knurling handle, socket wrench 1/2'' Drive Extension Bar,socket wrenchSpecification: 1/2''- 3'', 4'', 5'', 8''.10'' Material: alloy (chrome vanadium steel)socket wrench surface: chrome platedextention bar with overall heat treatment 1/2'' Drive knurling handle,extention bar