Fast 2K Post Back Fill For 5 Inch Posts | Single Pack | ANPT-FAST2K-5 For 5 in. x 5 in. posts | Use 1 - 26 oz. bag per post hole | Hole needs to be 36 in. deep with a 8 in. diameter No more handling heavy bags of concrete: one 26 oz. bag replaces two 50 lb. bags of concrete No water required | For use with wood, vinyl, or metal posts No messy concrete mixing Same advanced technology used to set utility poles for almost 15 years