IVY Classic 44775 1/4 x 3-5/16" Mega-Magnetic SDS Bit Holder, 1/Card 40X THE PULLING POWER: Mega-Magnetic Bit Holder features 2 powerful magnets which create 40x the pulling power of an ordinary magnetic bit holder (Mega-Magneticis a Registered Trademark) TWO POWERFUL MAGNETS: The internal magnet (#1) holds and magnetizes the bit while the outer circular ring magnet (#2) powerfully holds your fastener in place - see photo IMPACT PLUS: One piece stainless steel construction with aluminum slide is designed to withstand the high torque of drills and impact drivers(Impact Plus is a Registered Trademark) VERSATILE: Works with all 1" hex insert bits, designed for rotary use only. PATENTED IN USA: Size 1/4" hex, Length: 3-5/16", Shank: SDS Plus