Thanks to Hasbro, Medicom also did the two-stage helmet removal system
Stage 1 - Vader's mask revealed, with helmet attachment clamps and magnetic latch on top and at the sides as well as body heat regulators above the visual enhancement sensors and the air intake/output vents.
Stage 2 - Lower jaw and neck support durasteel shell revealed, showing the voice processor and nutrient feed tube at the front as well as multiple power cells and power distributor at the back. Anakin's (Sebastian Shaw played Darth Vader unmasked) disfigured face as seen in Episode VI when Luke unmasks him towards the end, where he utters, "Now go, my son..." before the 2nd Death Star explodes. Note the removal of Sebastian Shaw's eyebrows to emphasize the injury that Anakin received in Star Wars Episode III. For the Hasbro version, he still had his eyebrows.
This is the Star Wars Episode VI: ROTJ (Return of the Jedi) version Medicom released first. Medicom released a 2nd Darth Vader based on Star Wars Episode III: Revenge of the Sith (ROTS) version with the burnt out face of Hayden Christensen. Not too keen on the 2nd version. Medicom did the same thing with their Snake Eater from Metal Gear Solid 3 i.e. re-release figures when there's overwhelming demand.