Not certain where this expansion chamber came from? Some have suggested the brand Torque Engineerin.
Its total length is 100cm, its exhaust flange bolts are 6.5 cm on center, the Inside diameter of the exhaust pipe is 3.7 cm. Silencer is stampe J&R1-125
please measure your engine exhaust port. to make certain this product will fit.
Here is a video of a Yamaha 100cc LT2 with a torque engineering pipe on it.