This is the most common relief valve on all ball lock kegs. If you do have a lever tab second hand ball lock keg, you can switch it out with one of these.
NOTE: This is a safety device designed to release pressure at the approximate rated pressure. THIS IS NOT TO BE USED AS SPUNDING VALVE. The pressure rating on these is approximate with tolerance of +/- 10psi. If you need accurate pressure control to hold residual pressure in a pressure fermenter or pressure vessel we would recommend using the BlowTie.