Manufacturer PTSLKHN. PTSLKHN 20-piece hex head / Allen wrench drill bits in the following sizes Drive Bit Shank Style Hex Shank. Material & Durability of Allen Wrench Drill Bit Set: This allen wrench drill bit set is forged from high-grade S2 alloy steel and treated with vacuum high-frequency quenching, reaching 58-60 HRC hardness.
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