The SRAM Piston Massage spacer is specifically designed for aiding in brake setup and feel. The purpose-built tool replaces the need to stack two rotors when advancing caliper pistons all the way out during a piston massage procedure.
 
Features
Unique design fits all SRAM brake calipers apart from Monoblock calipers
It improves lever throw, giving consistent and reliable bite point
For instructions, refer to the SRAM Mineral Oil MTB Disc Brake Bleed Manual