I got tired of printing out models that wouldn't fit my calipers. This will fit pretty much every 6in calipers I could find, maybe a bit loose on some, but it will hold them. I also didn't need the battery slots I keep seeing, I wouldn't want them on my printer shaking, and if they can't shake they can't be removed, so I put in a slot that is large enough for the cap end of a sharpie, should fit a deburring tool, or xacto knife as well.