MLA for Commercial Off-The-Shelf. This refers to the practice of sourcing and buying commercially available kit for issue in a hurry due to lack of foresight - rather like a Local Purchase Order but on a bigger scale.
It actually makes great sense, as rather than having a piece of kit that's undergone strenuous testing and development at great cost to the taxpayer - and is still invariably shit, using COTS, the squaddie might end up with something quite Gucci.
COTS particularly applies to Desert Boots, and some lucky bunnies have been issued some rather excellent boots, such as Pro-Boot, Lowas, Altbergs and Meindl Desert Foxes. Like a Leatherman on a 1098, who would've dreamt it?