1-3/4" Diameter Self-Feeding Bit Bosch parts keep your tools working their best for any application you can come up with, and Bosch bits are the most versatile parts of them all. Be it screwing, hammering, or drilling, Bosch has a bit for you. Features: 1-3/4" Bit Diameter 1-3/4" Diameter 1-1/4" Inside Diameter Bosch has been in the headlines of state of the art development for over 100 years. From the invention of the jigsaw to their ergonomic designed tools, Bosch as cared about the customer since they started business in 1886.