These are boxes designed to hold wire spools 80mm diameter and 30 mm thick. They have 3mm holes for the wire and having a wire hole on each end the Box End file can be either left or right. Use separately or print two ends and as many middle pieces as you want and glue them all together works great with spools made with the Parametric Wire Spool by grob6k. Many thanks to grob6k https://www.thingiverse.com/thing:1782398