Hydrocaps replace your existing battery vent caps, and actively recombine the hydrogen and oxygen gasses that escape from a battery during normal use, with a platinum-based catalyst.

This reduces the need for adding fluid to your batteries, as well as minimizing potentially dangerous accumulation of hydrogen gas in your battery storage area and helping to keep the tops of your batteries cleaner.

These 3/4" threaded hydrocaps (measured not including threading) fit most batteries not listed under the Bayonet or Push-In style listings.

Cap will add about 2-1/8" to your battery height and is 2-3/8" diameter.