Key strips were used to enable single-line phones to access multiple lines and put calls on hold in a 1A2 phone system. Some models required a slight modification in the hookswitch wiring of the phone. The strips were made in different formats and could be mounted on a wall, a shelf, under a desk or shelf, or just sit on a desk or table near the phone. Key strips came with 25-pair cables. They are no longer being made, but we have a few. Please call 1.888.225.3999.