CRL Black 1/4" x 3/8" Tremco POLYshim II Butyl Architectural Ta.... Condition is New. Single roll. Continuous Integral EPDM Shim 100% Solids Content Used in Compression Glazing Systems The continuous rubber shim works to prevent sealant squeeze-out because it is resilient to pressure exerted by building and glass expansion or contraction. It also helps prevent glass breakage by eliminating pressure points created by improper shimming. The continuous shim eliminates the need for preshimming the lite before installing the tape. Tremco Pre-Shimmed tape has good adhesion, heat resistance, sealant compatibility, and resistance to weathering. It can be used in conjunction with many glazing systems. Combined shipping available for multiple rolls. I generally ship quickly, however there are times when we are away and it could take up to a week to ship. Take that into account before purchase. .