This is the original Hayes Dominion bleed block for normal bleed efforts,  and piston servicing block that allows you to safely push the pistons out for cleaning, one side at a time.  No more accidentally popping a piston out of the caliper.

Chamfered bevel on both sides to push pistons apart, no more damaging pistons or pads with tire levers, etc.

NOTE, this listing is for ONE block, additional blocks ship for 99 cents.