This is a visually reconstructed copy of Prusa Research's P-Drill*. The drill was a part of the i3 MK2 to MK2s upgrade and was used to enlarge the bed mounting holes for U-bolts. The part was not included in the latest MK2.5S upgrade kit (and I couldn't find it online). Some similarities/differences between the K-Drill and P-Drill: * This takes a 1/8" drill bit (3.175 mm) * Two 12mm socket cap M3 screws are used to secure the bit * Two M3 hex nuts are inserted in the slots to capture the screws (but square nuts can also be used) * This is the K-Drill to distinguish it from the P-Drill \* https://manual.prusa3d.com/Guide/1.+Y-carriage+drilling/323