What are these fasteners called?

[minimull]

This is a pic of the mounting plate for one of my gun safes. I’d like to use something similar but larger to secure my toolboxes in the bed of my TJ and LJ. Anyone know what they’re called?

 

[RED97SE]

T-anchor bolt

 

[Shropshirewrangler]

Over here they are called "Antiluce cotters or drop locks"!

https://www.ebay.co.uk/itm/19346037...d=link&campid=5337789113&toolid=20001&mkevt=1

 

[minimull]

Thanks guys!