Automatic valves come with a corrosion-resistant ball checks. 316 stainless steel valves come with 316 stainless steel ball checks. These valves are designed for standard straights through flow with 3/4" vessel connections. These valves can be put together with highly durable Pyrex glass tube or high pressure tube of 3/4" diameter. Guard rods and a round Plexiglas cover are available to protect the glass tube.