what part is this? and how can i get a new one/fix it?

[lemon]

alright...well this is why my top doesn't seal all the way around, and its why i havn't been able to roll up my back window all the way durring the horrible thunderstorms we've been having the last few days

soooo what part is this? and can i get a new one? and hows it go in? , it looks as if the old one sheared off? does it look that way and its just pressed in or what? ........i need help

this pic shows the spacer, between the 2 tracks/ pieces of metal


this pic has it missing, it's between the 2 tracks/pieces of metal


i just wanna put my windows up and not worry about the rain !