estate sale u-bolt kit - round - new / unused measurements - 3" x 7" x .5625" - 18, raw these are normally used for trailer axles, which means that they are of _exceptionally_ high strength and durability other limited only by your imagination just for giggles, check out what the dinky u-bolts you normally get around the 10 dollar mark. :) ! https://www.homedepot.ca/en/home/categories/building-materials/hardware/fasteners/bolts/u-bolts.html