On balance rods says 1010.the metal part is 11 inces long.i need window top plastic caps also

Thanks for posting. I'm sure we can help, but I need to see the attachment on the other end of the balance to fully identify it. That stamp is not an identifier; it just tells us the balance's strength. As for the Top Sash Guide, let me know if the 18-009 matches what you have, or if it differs in any way.

Detail of 18-009

Side view of 18-009