Simpson Strong-Tie® Quick-Zip Bar Booster® spacers are designed to support a reinforcing steel cage within a drilled shaft with a 3-in. concrete cover requirement and fit rebar sizes #3 through #14. They are also great for supporting reinforcing steel over waterproofing in mat foundations and providing vertical support of slurry wall mats. Quick-Zip Bar Booster® spacers are made of durable, noncorrosive plastic. The zip tie used for attachment is made of 170-pound tensile strength resin.