This is a T-Track insert for an in expensive T-Track with two M4 x 1 threaded holes. 80mm long. See over all dimensions in one of the images. I printed in PETG and accounted for shrinkage in the model.  Fits a T-Track measuring 3/4" by 5/16" or 19 mm by 8 mm. The hole spacing is 40 mm and 20 mm from each end. This insert was made to fit the stop block seen here: [https://makerworld.com/en/models/524984#profileId-505403.](https://makerworld.com/en/models/524984#profileId-505403.)