What is a ACT 2100?

The ACT 2100 and 2600 are clutches manufactured by Advanced Clutch Technology. They are popular clutch upgrades for DSMs.

Unfortunately, the 2100 and 2600 designations don't match the part numbers shown on their website. The correct part number for the ACT 2100 kit (disc and plate) is MB1-HDSS; the ACT 2600 kit is the MB1-XTSS. Check out the kits for the part numbers of the respective friction discs and pressure plates.