AliMed 18 Month Sensor Pad Chair Alarm Systems are a great option for alerting caregivers to potential falls. The sensor triggers an audible alarm when a patient attempts to rise off the pad. The moment the patient"s weight has been removed, the caregiver is instantly alerted by the sounding alarm. The pads are thin, non-restrictive, less detectable by patient so the risk of patient tampering is lower. Easy to use, simple setup. Urine-resistant. 10"Wx15"L pad. How it works: The alarm is triggered when patient"s body weight is lifted off the pad. The alarm resets when pressure is reapplied to sensor pad. AliMed Basic Sensor Alarm is your reliable standard patient alarm. When used with the nurse call jack, alarm sounds both locally and at the nurse call station. Mounts easily with clip at back of unit.