As technology improved and operational knowledge grew, Oceaneering upgraded their fleet of JIMs. The magnesium construction was replaced with glass-reinforced plastic (GRP) and the single joints with segmented ones, each allowing seven degrees of motion, and when added together giving the operator a very great range of motion. In addition, the four-port domed top of the suit was replaced by a transparent acrylic one that was taken from Wasp, this allowed the operator a much-improved field of vision. Trials were also carried out by the Ministry of Defence on a flying Jim suit powered from the surface through an umbilical cable. This resulted in a hybrid suit with the ability of working on the sea bed as well as mid water.