I have Hallmark windows series 210SH aama/awwda 101/I.S. 2-97 H-R25-47x71
The block and tackle broke on 1 side. I was able to find the replacement for the pair. The top cap and this (see the pictures) still need to be replaced. No one seems to know what this piece that is in the bottom of the window. It is aluminum and bolted in with this exceptionally long bolt. It doesn't seem to attach to the block and tackle in any way...just guides it. The top cap seems to hold down the B&T in the window channel. I don't have good measurements of this piece due to its small size. The top cap is 1" sq top, length 1 1/16", back with hole is 11/16"
I hope these measurements help.
Thank you. Regards, Bridget