A hollow shaft rotary encoder, also known as a hollow bore or through-bore encoder, is a type of rotary encoder with a central opening or hollow shaft through its centre. This design allows the encoder to be mounted directly onto a shaft or an axle, and the shaft can pass through the Centre of the encoder. The encoder can then rotate along with the shaft..Jayashree Encoders provides h... https://jencoder.com/hollow-shaft-rotary-encoder/