This is a flow sensor replacement o-ring used in the Bestway, Coleman and Lay-Z-Spa brands of inflatable hot tubs. This seal only fits the older egg style water flow sensors. This does not include the two smaller o-rings on the input and output pipes. If you find that your pump/heater unit is leaking water around your water flow sensor, the seal inside of the cap may be damaged. This is a high quality replacement silicone o-ring to replace your worn one under the cap. If you are replacing the flow sensor o-ring, check your flow sensor cap and the flow sensor magnetic paddle for damage. If you have a damage flow sensor cap, you can get my replacement by clicking this link. IF you need a replacement magnetic paddle also, you may want to look at my kit that contains the o-ring, the nylon retaining pin and the o-ring seal by clicking here.