For LC-20AT pumps, and for SIL-10ADvp, SIL-20/30/HT Metering Pump. Optional seal for the LC-10ATvp, requires the use of alternate spacer 228-35147-00. Original equipment polyethylene seal for LC-10ATvp is 228-21975-00. Please note that 228-35145-00 is for the metering pump of the LC-2010/2030/2040.