No markings whatsoever

I hope you can help me. I don't even know what these white plastic things are called, but they attach the window to the cords which ultimately attach to long springs in the sash (I believe it's called). Most of the windows in the house wouldn't stay open, they slam shut when unlocked, and I traced it back to these broken pieces. I temporarily used pop can pull tabs as replacements until I can find the right part.