SP-281TT RPM Kit, LMI Unidose Liquid End RPM Kit. The Kit includes the following parts: 4- Part # 50509-1, Male and Female Ferrules 4- Part # 48349, Polyprel O-Ring 3- Part # 37338, PVDF/Polyprel Cartridge Assembly 1- Part # 48795, Injection Cartridge Assembly 1- Part # 30917, .09 Fluorofilm Liquifram 1- Part # 10973, Shaft Seal These parts should be changed out every One to Two years.