Transvac couplings are designed specifically for use in the fishing industry (suction or low pressure discharge). They are used on Transvac pumps and they provide quick and easy installation of fish suction hose. Due to the unique construction of these fittings, maximum pressure rates vary depending on fluids, temperatures, installations, and specific applications - but as a guide the maximum pressure in 10" size is 25 psi. In order to connect, the male and female rings/stickers are inserted together (must use an O-ring as well) and the V-retainer clamps fit over the outside to hold the 2 halves together (use a rubber mallet to tap around the V-retainer clamp to ensure the best seal). It is also recommended to lightly oil/grease the O-Ring prior to installation for best seal and replace O-rings when aged/worn. For "quick connects" in 10" fish transfer applications, some users prefer the Aluminum Travis HPRL Ringlock System (running them 'backwards', i.e. ensuring the male end is on the receiving side of the connection to ensure no damage of fish being transferred).