a steel tape which coils up into a metal case installed in the head jamb of a window frame; the end of the tape attaches to each sash, providing activation or balancing; “overhead balance” when installation is in head jamb; patent balance.
a steel tape which coils up into a metal case installed in the head jamb of a window frame; the end of the tape attaches to each sash, providing activation or balancing; “overhead balance” when installation is in head jamb; patent balance.