Features: 1.With the full hitch arm and hitch connector, easy to install with no other tools required. 2.This tow bar adpator can be compatible with universal bicycles and electric bicycles. It is very practical. 3. Good quality: This product is made of durable metal material, very sturdy and durable, and it is very durable. 4. Portability: This product is small in size and light in weight, easy to carry, you can carry it when you travel and ride. 5. General: use the same type of coupler as other brands of trailers. compatible for most common bicycles, most bicycles can be used. Description: This tow bar adpator can be compatible with universal bicycles and electric bicycles. It is very practical. Specifications: Hole diameter of bicycle bolt: 11 mm Hole diameter of trailer handle bar: 7 mm The diameter of the recessed area where the shaft nut is screwed: 21 mm Base plate length: 55 mm Package Included: 1*Replacement Coupler Hitch(with crasp) Notes: 1. Please allow 0-1 inch error due to manual measurement. Thanks compatible for your understanding. 2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from real object.