Water Filter Opening Handle Ring Spanner Wrench for 10" x 2.5" Filter Housing Suitable for AQUAPRO and other 10" x 2.5" Water Filter Housings both Counter Top and Under Sink Units with Similar Profile. Check Image for Dimensions and Profile of Filter Spanner. Suitable for unscrewing Filter Housings with four rib profile. Internal Diameter of Filter Spanner is 108.5 mm and the four lugs protrude out 4.25 mm.