The Sandroid makes it possible to profile fine detail onto floor slabs, walls, and ceilings. The tool is used usually in combination with stencils. It shoots a blast media through a nozzle which then vacuums up the blast material along with the residue from the concrete, sending it back to the machine where the blast media is recycled and sent back to the nozzle for reuse. The dust is stored in the canister. The filter mechanism allows for long-term use without disassembly and cleaning. Engrave-A-Crete. 800-884-2114. .