The MVR-3 Mini Sub actually began its life as the MVR-3 speeder bike. Commonly used in the military and piloted by droids, the MVR-3 speeder had an unusual design and was equipped with a front mounted blaster and a small storage compartment at the rear of the craft.
The hydrodynamic adapter kits, used to convert the MVR-3 from speeder bike to mini sub, were provided by Xi-Char engineers for design flaws on one of their previous submersible products. The conversion kit changed the frame and adapted the systems for underwater use; the storage compartment and front mounted blaster remained.
The modifications didn't disappoint and the MVR-3 was used as a support craft and worked rather well in tandem with the larger warships in underwater fleets. It served reliably and with distinction until being quietly pushed aside by more advanced models. The remaining units were again modified; this time to accommodate a living pilot. They were then sold to the public, where they are still occasionally seen in service.