This is The NordClamp, an accessory for the NordStick, a device used for Nordic curls.

It allows you to perform Nordic curls by securing your feet to a vertical beam.

The clamp uses Velcro to attach to fixed vertical beams.

It is designed to be used with the NordStick, which slides under a door to secure your feet for Nordic curls.

This setup offers a portable way to do Nordic curls at home.