|LEGO → System → Aquazone → Hydronauts|
6110 Solo Sub is the smallest Hydronauts set released. It is a small underwater vehicle piloted by Crystal Miner. The set has one propeller and no weaponry, but Crystal has two attachments to her armor, which are both lights and possibly weaponry. The cockpit of the set is large enough to fit one minifigure, but the armor attachments must be removed to allow Crystal to go inside; they are instead placed on top of the vehicle as weapons when removed from Crystal.