For LC-20AT pumps (with spacer 228-42700-00), and for SIL-10ADvp, SIL-20/30/HT, LC-2010/2030/2040 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.