The Blastcrete Model RD6536 Squeeze Pump hydraulic concrete pump attachment offers variable speed from 0-25 cubic yards per hour. This concrete pump attachment is successfully used for pumping grout materials, 3/8-inch shotcrete, and 3/4-inch structural concrete mixes. The hydraulic oil requirement for the RD6536 is 18 gallons per minute at 3000 PSI. The primary wear part on the pump is the 3-inch rubber pumping tube that can be replaced in the field in 20 minutes. These are the most simple and safe concrete pumps on the market to maintain and operate. Since no concrete material comes in contact with the moving parts of the pump, you will be pleased with the life of this machine.