I needed risers for my bed so that it would be tall enough to fit a rolling storage bin underneath.

It raises the bed by roughly 2 inches (50mm, to be exact). And the recess is designed to fit bed legs that are 3 inches (or 76mm) in diameter. The legs are wider at the base to avoid the risk of them tipping over when you are… let's say jumping… on the bed.

I printed in PETG, but PLA should work fine too I suppose. The included print profile is super beefed up so it's strong enough to support the weight (10 walls, 20 top/bottom layers, 30% rectilinear infill). This thing is solid.