Blend of fast-setting cements, sand and gravel. Designed to set hard in approximately 20-40 minutes. Sets posts without mixing. For setting fence posts, mailbox posts, lamp posts and swing sets. For building steps, sidewalks and air conditioner pads. Used to set mailbox posts, fence posts and lamp posts without mixing.Pour dry mix into hole and soak with water.Also use for building steps, sidewalks and slabs where rapid set time is required.Exceeds the requirements of ASTM C387.Each 50 lbs. bag will yield approximately 0.375 cubic foot of mixed concrete.