The Grind Machine was the very first release in YoYoFactory's Redline (now known as Project Red Alert) series, and their first metal yo-yo that did not use the F.A.S.T. response system, instead coming included with three sets of interchangeable response pads, each made of a different material for a different feel. The pads can be mixed and matched so that the user could adjust the yo-yo's responsiveness to his or her own personal preferences.