223/5.56mm Bore Brush, #8-36 ThreadChamber brushes have the core wire looped through a brass coupling, threaded #8-36. The chamber brush is configured with two brush diameters; the first stage of phosphor bronze cleans the chamber area, while the second stage of stainless steel cleans the bolt lock up area. · chamber brush GI style threads· Fits into 5. 56X45 Nato chambers· Bronze bristles to remove carbon· Will not damage chamber· Durable and long lasting Length: 3.6″ Weight: 0.3 oz. · tem : NSTARTBCAR15· SKU : TBCAR15· Model : Chamber Brush UPC : 814108013714Please note that the #8-36 coupling is not a standard thread size and will not fit most commercial cleaning rods. However, these will fit most Kleen-Bore multi-section rifle rods found in the Classic Rifle Kits and the All Caliber (S-170) Rod Set.