The straight-line attachment, which fits into the low-speed handpiece, has a long, straight shank. It works best on soft tissue such as muscle or fat. The straight shank allows the surgeon to see exactly where it is being inserted into the bone. The curved-tip attachment, which fits into the high-speed handpiece, has a shank that is bent slightly at the end. It makes cutting into hard tissues like bone easier than using the straight-shank attachment. The tip of the curved shank can be flat, rounded, or pointed. Both types of attachments are used for making holes in bone for screws or other implants. The straight-line attachment is used with slow speed (250-500 rpm) while the curved-tip attachment is used with high speed (3,600-7,200 rpm). Also called drilling attachments.