Special hole saw of HSS Bi-Co with constant tooth pitch to install roller shutters in window frames. Incl. hexagonal shank and pre-drill bit to place the hole saw in position. During the installation of the roller shutter you have to drill holes in the window frames for the belts. This was always an issue, but with this hole saw it is properly solved. Remove the pre-drill bit from the hole saw after the fi rst cut. This reduces the cutting forces and it works much more easier.