Shimano Bike Hydraulic Disk Brake Caliper Spacer Block

Used when transporting bikes when rotor isn't in the caliper i.e. when you remove your wheels. It stands instead of your rotor in case the brake lever is pulled while the wheel is out causing the piston(s) to potentially unseat from the cylinder(s). Suits a wide range of Shimano calipers. You can usually get them from your local bike shop for a couple of dollars but why not print them for a few cents!