This is called a transport ball screw. There are ball bearings inside the block that recirculate as the shaft turns moving the block back and forth on the shaft. These convert high torque rotary movement into precise linear movement with low friction. They can be mounting in any position needed and attached to a motor or hand operated. These are made by numerous companies and have slightly different designs. The URL shows some that are most like yours. The maker of yours is unknown.

This is called a transport ball screw. There are ball bearings inside the block that recirculate as the shaft turns moving the block back and forth on the shaft. These convert high torque rotary movement into precise linear movement with low friction. They can be mounting in any position needed and attached to a motor or hand operated. These are made by numerous companies and have slightly different designs. The URL shows some that are most like yours. The maker of yours is unknown.

References:

https://www.abssac.co.uk/p/Ball+Screws/Transport+Ball+Screws/41/