When you really need to put some torque on a screw, or you need to work in tight quarters, these can be a life saver. Just pop the adapter onto your 3/8" drive ratchet, and slip in a 1" long hex insert bit. (Don’t use ball detent bits in this. They’ll be stuck forever - believe me!) Now you can choose either magnetic or non-magnetic! Please note that the magnetic bit holders are longer to accommodate the magnet. Made in USA.