From Mr. HVAC This is the absolute best multi-type nut driver I have owned and used. This tool is larger than in looks in the picture. It is heavy and very solid. Most HVAC technicians will encounter 1/4″ and 5/16″ all day long. 3/8″ and 1/2″ are also handy. This driver has those sizes and more. Hollow shafts and magnets offer greater usefulness. Adapted from Amazon 7-in-1 Nut Driver, Magnetic Driver with SAE Hex Nut Sizes and Spring Coil Bits, Heavy-Duty Handle for Added Torque Seven sizes in one tool! All sizes allow for easy, one-handed driving. The sizes are interchangeable ensuring you have the size you need when you need it. Color coded shaft ends make it easy to identify the size. Heavy-duty handle and shaft exceed the torque performance of regular nut drivers. Wrench-assist on handle for added torque on tough jobs. Color-coded bands for easy identification. Hollow shafts (1/4″, 5/16″, 3/8″, 7/16″, 9/16″) for driving nuts deep onto bolts or threaded rod. Spring coil (7/16″, 9/16″) holds nuts and bolts in place without the use of magnets. Strong, rare earth magnets (1/4″, 5/16″, 11/32″, 3/8″, 1/2″) securely hold nuts and bolts.
