Review for LEGO set 6150 Crystal Detector from Brickipedia
“The Crystal Detector is one of the larger Hydronauts sets. It has a suction cup gun to hold on to Green Crystal Storage Boxes. It comes with one Hydronaut, who has special armor light, which can be taken off and attached to the Crystal Detector. It is a ground vehicle, but... More it uses propellers to speed it through the watery depths. It has two Chrome Silver Harpoons and Lights/Sonar Emitters.”
Full review at brickipedia.fandom.com