Black replacement EZ Twist Cap with O-Ring for Aqua UV Classic Units Includes: EZ Twist Cap is about 3-3/8" diameter O-Ring is about 2-3/4" diameter Fits Standard Units
O'Ring For Strainer Basket Lid . Fits the lid on the standard 90 cubic inch standalone basket as well as the lid on the Champion Series Self Primers such as the 3700PRM21, 4900PRM21, 6600PRM24...