LMI Uni-Dose Liquid Handling Assembly Part #30995, Uni-Valve Asm., Macroflex/ THIS PRICE IS FOR ONE UNI-VALVE. This is a part most commonly needing replacement when pump finds trouble priming. Four of these are included in the SP-281 Spare Parts Kit. These parts can last from 1 to 5 years. There are four valves in every pump.