This is a tough one. If you have a Series 400, there is a good chance that your window is an older style that isn't meant to be removed. This will make identifying the proper clip difficult. Would you be able to open the sash and show us a picture of where the clip is from the bottom? It won't be a perfect picture, but we may be able to make out some clue as to what will work for you.
Thanks for getting back to us. This sash definitely can't be removed. You do have a screw on side clip, though. Looks like you could use needle nose pliers to straighten out the arms that hook on the Series 400. If they're broken, you might be able to use our 17-094 clip on bracket, but I'm not sure you have enough lip to hook this clip on.
Also, when buying a replacement for the Series 400, you might also want a 75-005 charging tool to help install and charge them.
