PROMAX brake post extender made by carving 6061-T6 aluminum by NC machining can be attached to the existing cantilever brake boss to shift the brake arm position up about 16mm.
What that means is that it's a great product that allows you to convert a 26 inch frame to a 650b or a 20x1.75 BMX frame with 20x1-1 / 8 race tires.
It must be a removable canch / V-brake pedestal to install this part.
Weight: 32g (including bolts)
Bolt size: M10