This listing is for 2 Milwaukee Brush Holder Assemblies (part #22-20-0120).  

It's compatible with the following model (CAT) numbers:

6088-20 (SER 994D) Sander/Grinder
6080-20 (SER 988A) Sander
6086-20 (SER 991B) Grinder
6080-20 (SER 988B) Sander
6089-20 (SER 992A) Grinder
6080-20 (SEC 988C) 7"/9" Sander
6081-20 (SER 989A) 7"/9" Sander
6081-20 (SER 989B) 7"/9" Sander
6081-20 (SER 989C) 7"/9" Sander
6082-20 (SER 990A) 7"/9" Sander
6082-20 (SER 990B) 7"/9" Sander
6185-20 (SER A20A) 14 in. Handheld Cut-Off Machine
6185-20 (SER A20C) 14 in. Handheld Cut-Off Machine
6086-20 (SER 991A) 9" Grinder
6086-20 (SER 911C) 9" Grinder
6086-20 (SER 991D) 9" Grinder
6088-20 (SER 994A) 7" Grinder
6088-20 (SER 994B) 7" Grinder
6088-20 (SER 994C) 7" Grinder
6089-20 (SER 992B) 9" Grinder
6089-20 (SER 992C) 9" Grinder
6086-20 (SER 991C) 9" Grinder
6088-30 (SER B43A) 7"/9" Grinder With Lock-On
6088-31 (SER B44A) 7"/9" Grinder
6089-30 (SER B45A) 7"/9" Grinder With Lock-On
6089-31 (SER B46A) 7"/9" Grinder