The SF570 Pendant Transmitter features the great range and reliability of 433 MHz in a small waterproof package. The pendants can be worn in the shower or bathtub, outside in the rain, or other environments where they may be splashed with water or momentarily submerged. The pendants have a single-button design with "press and onesecond hold" activation, making them easy to use but resistant to false alarms. When a pendant is activated its red LED stays solid for five seconds, then blinks slowly until the alarm is cleared. Alarms may be cleared by placing an RP570 Alarm Clearance Card over the button.