Check the listing for details. Pentair Pentek SW1A SW2 SW3 Spanner Big Blue, Slim Line Housing Filter Wrench. Color: Black, Condition: New. Listed at 11.29 USD. Pentek SW-1A # 150539 SW1 Slim Line Water Filter Housing Spanner Wrench Compatible With Culligan, Ametek, US Filter, Plymouth, Kleen Plus, American Plumber, Bruner & Many Other Brands. SW-1 Water Filter Housing Wrench. Fits 4" Slim Line Housings. (Slim Line Housings Have A 3 1/2" diameter "O" Ring) Ametek # 150294. Only for use in loosening filter housings, never to tighten. Overtightening may cause damage to the O-rings and make re-opening VERY difficult. Hand tighten only. Fits most standard style RO systems. Pentek SW-2 # 150295 SW2 Standard Size Water Filter Housing Spanner Wrench Compatible With Culligan / Ametek / US Filter / Plymouth / Kleen Plus / American Plumber / Bruner & Many Other Brands. SW-2 Standard Size Water Filter Housing Wrench. Fits 4 3/4" Standard Size Filter Housings. Pentek SW-3 Water Filter Wrench. This wrench fits most standard Big Blue 10"x4.5" and 20"x4.5" housings, including Pentair / Pentek, American Plumber, Ametek, US Filter, Culligan, Crystal Quest and others. Use this SW3 wrench to loosen the bottom part of the housing during filter replacement. Always in stock, ship on the same day!