This is a PCR rack holder that tilts the rack 10° towards you, so that you can read the labels and see inside the wells without having to crane your neck. It accepts this kind of PCR tube rack, dimensioned at approximately 128 mm long, 88 mm wide, and 15 mm tall:
The pictured example is sold by Sigma-Aldrich, but the same basic design is sold as a rebranded item by many other sellers, for example here and here. Just look for the funny lugs on the sides of the rack, which means that it can hook into a PCR workstation.
You should add some self-adhesive rubber feet to the bottom of the holder when it's finished. Choosing tall feet will give the holder enough clearance from the table to fit skirtless 96-well PCR plates, with the wells poking through the big hole. Of course, skirtless plates fit straight into the racks themselves (as shown in the preview photo above), so it's your choice.
To fit a PCR rack, slide it in from the top. The holder narrows towards the bottom, pinching the rack and holding it in place.