What are these called? (1 Viewer)

[FJBen]

I'm looking at making something similar to this pop-out window, but for the life of me I can't figure out what the "latches" are called. I believe they just twist to hold into place which makes me think they are quarter turn latches, but those usually open from the outside. That might work but I'm open for other ideas that doesn't look like big handles on the outside.

Disregard hinge in this picture.

 

[jblueridge]

Mcmaster Carr sells Turn Latches.