This small piece mates a piece of “blackpipe” from the hardware store to the top of a 100gal stock tank. This is a very common method of suspending a heat lamp so the tank can be used as a brooder. 

The benefit of this item is that with one of these in place on each end the bar cannot be slid or knocked off the top of the tank reducing the risks associated with heat lamps. 

Hope someone else finds it handy!