Unique, patented head slides back and forth to switch from 1/4 in to 5/16 in magnetic hex-head screwdriver. Convenient thumb nut locks tip setting. This HVAC multi-bit driver includes a specialty bit for the installation/removal of common TR-4 Schrader® valves as well as regular 1/4 in and 3/8 in nut drivers plus Phillips®/slotted double-ended bits. Offers the HVAC tech the convenience of having magnetic nut drivers on a multi-bit screwdriver.