I've always known is as a "viewing box." Have used them to see in the midts of all the ripple.
If youre worried about dunking the camera in water, you dont really have to put the camrea _inside_ the box, you can take a picture from half arm distance, standing on top of the tank. Snap a clear picture thru the bottom of the box as the box is a few inches submerged in water, but not entirely. The handle is a clever idea to keep your hands dry which is better since you're handling a digi cam that shouldnt be getting wet.
JOHNNY