Comparison : Item # B579-2, Replacement Flat Brush (Without Holder), 2 1/4" X 3/8" Nylon Bristles
Item # B579-3, Replacement Flat Brush (Without Holder), 2 1/4" X 3/8" Stainless Steel Bristles
Item # A2087-2, Flat Brush With Standard Holder, 2 1/4" X 3/8" Nylon Bristles, 5/16"-24 Female Inlet
Item # A2087-3, Flat Brush With Standard Holder, 2 1/4" X 3/8" Stainless Steel Bristles, 5/16"-24 Female Inlet
Item # A2087-5, Flat Brush With Standard Holder, 2 1/4" X 3/8" Nylon Bristles, 1/8" Female NPT Inlet