Locksets

Does anyone know where the T locks come in the barn yard builders use?

I'm looking for T locks barn builders yard use. It seems a garage door "T" handle. However, the shaft is longer and the catches on the inside of the door looks like a metal "D" which is probably about 4 inches wide inside. It joins the shaft with a allen head screw. I looked everywhere for a supplier of these locks. Does anyone know where I can buy? Thanks to everyone who has provided a response. I should clarify that I really want to buy these in bulk quantities.

If you are a Menards the Farm and Fleet have to have them and can place orders, both Lowes and Home depot