Pack of {5} -- 10"-20 teeth (blue) "HAWK" HYBRID -- Brush Specialty - Carbide Tipped Trimmer Brush cutter Blades, by RENEGADE BLADE BLADE ATTACHMENT PARTS: Our blades are "Universal Fit" provided you FIRST acquire "Blade Kit" parts for your Trimmer model, (we don't sell these parts). IMPORTANT>> A blade does {NOT} fit directly on the tiny 5/16" axle that the "String Spool" screws onto, ALL string trimmers require some type of blade mounting parts (normally 2 small discs, nut, and cotter pin) to run a blade (YouTube can show this). We offer TWO arbor sizes: 25.4mm (same as 1") & also 20.0mm with reducer washer. CARBIDE -- is estimated to last 10x longer than plain steel but does not cost 10x more creating incredible value. The CARBIDE MIX in our teeth is proprietary and 2nd to none. SIX BLADE TYPES -- All 6 specialty types of blades we offer are as follows: (1) Silver RSB. thick tree limbs thick brush: 8-80t, 9-100t, 10-120t... (2) Yellow TALON Hybrid, thick tree limbs & hard brush: 8-72t, 9-84t, 10-96t... (3) Red RAZOR Hybrid, medium limbs & thick bushes: 8-56t, 9-68t, 10-80t... (4) Green VIPER Hybrid, small limbs - brush & brambles: 8-44t, 9-48t, 10-52t... (5) Silver RSB, brush & brambles: 8-32t, 9-36t, 10-40t... (6) Blue HAWK Hybrid, brush only: 8-20t, 9-20t,10-20t. RENEGADE BLADE is the ONLY Carbide Brush Blade BRAND on Amazon that has a {REPORT} from the foremost Testing Laboratory: UL, LLC. UNIVERSAL FIT -- each blade comes with a "REDUCER WASHER" allowing blade to fit either 1" (25.4mm) or 20mm Arbor Hole sizing with your "Blade Hardware". --- BLADE HARDWARE: A Blade will {not} fit onto the Trimmer Axel Shaft by itself like the String Line Dispenser Spool will. So you must acquire "Blade Hardware" (mounting / adapter parts) that consists typically of two small discs; one has a raised circle on it that the blade hole fits onto, the 2nd small disc is the cap disc, then screw on the Nut and apply a Cotter Pin. Sorry, we DO NOT supply blade hardware. --- Carbide is estimated to last 10x longer than plain steel but does not cost 10x more creating incredible value. The CARBIDE MIX in our teeth is proprietary and 2nd to none. Just Tungsten is not enough; additives like: Hafnium, Tantalum, Titanium, Molybdenum, Silicone, Zirconium, Boron, Niobium, Chromium, & Vanadium, make for a better Carbide Mix for longer lasting teeth. Our blade is built for any RPM even super high RPM Trimmers (10,000+ rpm). Manufactured with a more flexible steel as compared to the much more brittle steel found with table saw blades (table saw blades can shatter if they hit an obstacle, plus they are only built for approx. 3,450 rpm so they should never be used with Gasoline powered Garden Trimmers). RENEGADE BLADE is the ONLY Carbide Brush Blade BRAND on AMAZON that has a {REPORT} from the foremost Testing Laboratory: UL, LLC. --- We Offer {FOUR-specialty} type Carbide BRUSH BLADES on AMAZON that you can find using SEARCH. --- We have a BLADE for any Garden & Field application you may encounter: (1) STANDARD Multi-use Blades: 8"-80t, 9"-100t, 10"-120t, (2) STANDARD Brush & Brambles Blades: 8"-32t, 9"-36t, 10"-40t, (3) RAZOR Hybrid Combination Blades: 8"-56t, 9"-68t, 10"-80t and, (4) HAWK Hybrid Brush & Brambles Blades: 8"-20t, 9"-20t. 10"-20t.