Warmshine spa mineral sticks compatible with most spa maintenance products & designed to fit most spas and hot tubs filters;compatible with ozonators & most suction-side and pressure-see filters. BUT ATTENTION PLEASE:OUR SPA MINERAL SANITIZER STICKS MINIMUM REQUIRED FILTER LENGTH IS APPROX 7",MINIMUM FILTER HOLE DIAMETER IS 1-1/4"!!! Warmshine silver hot tub mineral sticks significantly improves look & feel of water,assures an odor-free spa,improves performance of ozone-equipped spas,bring you crystal clear water. Warmshine spa mineral sticks for Spas up to 500 Gallons/2000L,Hot tub mineral sticks continuous keep your hot tub with low maintenance and in an nature eco friendly mineral way, effectively kills bacteria,viruses and alage safely and effortlessly. No more skin irritations,harmful bacteria viruses and algae. Low maintenance and low cost with a duration up to 4 months,easy to install and simplifies water balance,our spa mineral sticks for hot tubs unaffected by heat,works with your existing flow rates Installation,Just Simply drop the hot tub mineral stick into your existing filter and let the hot tub mineral sticks do their work. Alternative to heavy chemicals.spa silver mineral sticks reduces bromine and chlorine usage by up to 50% in most spas, without high levels of chlorine or bromine-low maintenance.You can now enjoy a safe Spa and Hot tub experience with healthier spa experience.