Allows Easy Control of Sealant Application Thickness Wont Adhere to Sealants - No Bond Breaker Needed Compatible with All Cold-Applied Sealants Easy To Install CRL Closed Cell Backer Rod is a round, flexible, closed cell polyethylene foam with an exterior "skin" used as a backing and thickness control device for elastomeric and other cold-applied sealants. The backer rod becomes an integral part of the joint into which it is installed and therefore is available in a range of diameters to accommodate joints from 3/16 inch to 1-5/8 inch. It limits the depth of the sealant, therefore preventing excessive use of sealants. Because the sealant will not bond to the "skin" of the rod, it can stretch and recover with joint movement, with minimal stress being put on the points of adhesion to the substrate. Oversized. Ship at UPS Oversize Rate. Diameter of Rod: 1-1/2 in (38 mm) Feet per Package: 102 ft (31.1 m) Package Contents: 17 pieces 6 ft long each CRL Closed Cell Backer Rod will not absorb water or wick water to joint walls which could cause adhesive failure. It is compatible with cold-applied sealants and its round shape promotes the preferred "hour glass" shape for joint sealants. Being easily compressible, it withstands hot and cold temperature extremes from -45° to 160° F (-43° to 71° C). It can withstand dynamic joint movement without shifting from position or losing its "grip" on the joint walls. CRL Closed Cell Backer Rod is chemically inert, and resistant to oils, gasoline and solvents. It will not stain or "bleed" into sealant material. Backer rod is typically used in expansion/control joints where cold-applied sealants are used. These joints would normally be found in curtain walls, construction partitions, precast panels, parking decks, door and window frame perimeters, coping, floor and deck joints, horizontal traffic joints and building