Ivy Classic 45834 3-5/16" Mega-Magnetic Bit Holder, 40 x the pulling power of ordinary magnetic bit holders and screwdrivers, One piece stainless steel construction, 1/4" Hex power shank. Mega-Magnetic Bit Holder - 2 powerful magnets create 40x the pulling power of an ordinary magnetic bit holder. Magnet #1 holds and magnetizes the bit while magnet #2 powerfully holds your fastener in place! (See illustrations), Designed to withstand the high torque of impact drivers. Works with all 1" insert bits, One piece stainless steel construction. 1/4" hex power shank. Patented in the USA.