I've got a couple of them, they are made by Tanos and from what I can tell they are made from the same material as the T locks.
The only down side to the Meta loc box's is they are not as easy to open if they are in the middle of a stack as the systainer that will be on top of the Meta loc box will loose it's full connection once you open the Meta loc latch. It can be done but you have to be careful with the box on top. So I would say that the Meta loc latches have two functions where as the T loc latch sytem has three.