6 Grobet Precision Screwdrivers Great For Watch, Electronic, & Eyeglass Repair. This is a new set of 6 precision screwdrivers Great for watch, electronic and eyeglass repair. Replaceable tips are held firmly in the handle by means of screw chucks. The blades are made of the best quality tool steel, which have been heat treated for toughness and long wear. The bodies are plated and have hexagonal swivel heads which will not roll on the bench. Each has an overall length of approximately 3 1/2" (89 mm). The tips are flat and measure: 0.5, 1, 1.4, 1.7, 2 and 2.45 mm.