This wrench slips onto the filter housing to aid in the replacement of filter cartridges, easy for using. for membrane cup design to prevent cracking. Fits all standard 10 inch water filter housings. Tighten specific law on the first hand clockwise filter bottle, so a half turn with a wrench to normal tightness filter flask and filter cover should have 1-2 mm cap. premium pp material, & long for time service., Manufacturer: Mllepjdh