AJAX DoubleButton User Manual page 10

Please note that Holder is sold separately.
The button is easy to carry around thanks to a special hole on its body. It can be
worn on the wrist or neck, or be hanged on a keyring.
DoubleButton has an IP55 protection index. Which means that the device body is
protected from dust and splashes. And a special protective divider, tight buttons,
and the need to press two buttons at once eliminate false alarms.