AquaValve 5.0 uses two different silicone sizes instead of only one size in the original model. The Autopot AquaValve 5.0 Replacement Blue Silicone replaces the BOTTOM silicone for the AquaValve 5.0, the original yellow/red silicone replaces the TOP silicone only for the AquaValve 5.0 and both silicones for the original AquaValve.