The TCS Ar-15, M16, M4, cleaning jag is made specifically for cleaning the Upper Receiver and Buffer Tube on these guns. It is made with pride in the USA. These patch jags press the patch that has been treated with solvent against the upper receiver or buffer tube to mechanically strip out debris that could inhibit your guns smooth functioning. These Jags are the only jag on the market designed to clean AR-15 Upper Receivers and Buffer Tubes. These patch jags work with the interrupted cuts in the AR-15 receiver and hold the patch during the scrubbing process. "The proof is on the patch". In addition to cleaning, this jag is also used for lubricating the Upper Receiver. Jag fit Mfg: Tcs