plastic clip, clips into window for the screw to screw in
A handy person says:
June 17, 2021
this piece in the window is what holds the 30" Series 600 Spiral Tilt with the screw
Dave Sr. from SWISCO responded:
June 21, 2021
Hello,
I believe the part you need is our 26-200 balance screw plug. Take a look and compare the specifications to yours, along with the other related parts. Thank you!