Never worry about where the pad is positioned on this sleek, black sling-seat wheelchair alarm by Drive Medical. The pressure-sensor pad â made from durable, reinforced vinyl â seals directly inside the wheelchair seat and features steel side-stays and is backed by an unconditional, one-year guarantee. It fits all popular sling-seat wheelchairs, which can be easily identified by the red tag sewn on the back of the sling. The system is shipped with the following: replacement seat/alarm, alarm box, mesh mounting back and 9V battery. (Not for use with heavy gel cushions.)