Super-absorbent cotton mop couples with tough, bronze and/or nylon brushes to clean a grenade launcher or tear gas tube in one easy step. The mop and both brushes have durable, aluminum, male and female couplers that let them attach to each other, in any order, so you can develop custom combinations to suit your specific cleaning needs. Sold in 3-Paks or 12-Paks. Mfg: Brownells SPECS: Fits 37 & 40mm launcher tubes. Bronze brush - Bristles, Phosphor bronze, wound-steel shank, aluminum coupling, 5/16" X"X 27 thread. Nylon brush - Bristles, Nylon, wound-steel shank, aluminum coupling, 5/16" X"X 27 thread. Mop - Wound cotton, twisted steel shank, aluminum coupling, 5/16"