Manual brake bleeding aid for two-wheelers. Where previously only two people could manually bleed a brake, this check valve now helps. One end of the hose is attached to an optional collection container to collect the excess fluid. The other end is attached to the nipple of the caliper. The nipple can now be opened and the brake lever can be operated without any worries until no more air escapes below. The check valve ensures that the air is not drawn back in. Please make sure that the expansion tank is always sufficiently filled with brake fluid (DOT) and is not emptied.