Internal Expanding Rear Brake Drum Assembly-90 mm

We call this our "Internal Expanding Rear Brake Drum Assembly-90 mm." Here is a curious little item, an internal expansion drum brake assembly. Unlike most small scooter brake units that use brake shoes that contract or clamp-down to provide the braking pressure, this brake unit's shoes expand outwards to grip the inside of the drum. External labeling states this is a "Servo Brake" from Xun Lin Brake.

This is an outside view the 90 mm unit. There is an almost identical 100 mm version in stock as well.