Little white piece with the crack in it. Most of my windows for that part are baked by the Florida sun and cracking SERIES 70007100
H-R40-48x72
H-R40-72x72
AAMA Certified program
American National Standard Institute
This is all the information I can get from the window. This part helps hold the window up when it is slid past it. These are tilt windows. Also the lever that you pull in to release the window to tilt are now breaking. That little yellow part In the one pic.