GearNews - Retra uTrigger Camera Remote
The uTrigger uses two modules to communicate magnetically through underwater housings, avoiding the need to drill holes or find a spare port. The transmitter can send the trigger signal to the camera’s receiver through 2cm-thick camera-housing walls. The aluminium hand trigger unit also holds two 9V batteries. The uTrigger is available direct from Retra from 299 euros plus shipping.