Culligan 1" HD SW-3 Wrench for Big Blue Housings, 1&quot Wrench for Inlet/outlet housing For use with Culligan Filter Sediment Water Filter HD-950 (1653-3556) This product is made in China Use the SW-3 filter wrench only for twisting off water filter housing canisters. Do NOT use the SW-3 housing wrench to secure the water filter canister to the water filter lid, damage may incur to o-ring. The SW-3 water filter wrench makes changing water filters easy. The SW-3 spanner wrench can be used with No.10 Big Blue whole house housings. The SW-3 wrench is slightly less than 6-Inch Wide. (Note: Width is less at the notches.)