Canister Housign Wrench
Available sizes:
SW-1 Standard - fits most undersink canister filter housings which accept 2.5" x 10" filters.
Sw-B Membrane & Standard - fits both canister filter housings and membrane housings like the Value Line 4 Stage RO System
SW-4 Big Blue - Fits large diameter Big Blue whole house canister filter housings which accept 4.5" diameter filters