Open cell backer rod is unique; it can easily
compress and return to its original state due to unrestricted air
movement. This flexibility makes it easily conform to sealing
applications and helps limit the depth of the sealant while also adding
good sealant airing, which can reduce drying or set up time. FillPro
Open Cell is a highly conformable “spool-less” backer rod available in
bags.
Open cell backer rods may not be ideal for sealants that are susceptible to bubbling of air escaping the backer rod material