The Edstrom Vari-Flo Drinking Valve is a very popular valve for use with mice, rats, gerbils, hamsters and birds because it is so easy to activate (can be used by weanling mice). The flow-rate of water from the valve can be adjusted by twisting the valve cap clockwise to decrease flow or counter-clockwise to increase the flow-rate. This model has a standard 1/8"mpt connection for threading into rigid PVC pipe lines. (The Fitting Tee Adapter PVC, 1630-2914-100, can be used for mounting in 1/2"PVC pipe). The valve is made of solid brass, with a stainless steel stem, and rugged elastomer seal and diaphragm.
How it Works: To drink, animals simply move the stainless steel stem by biting or licking, releasing water. When the animal releases the end of the stem, the elasticity of the silicone rubber diaphragm located behind the stem head pushes the head back to the closed position, stopping the flow of water.