Fourth Element
The Proteus Short John designed is to be worn underneath the 5mm or 7mm Proteus to provide enhanced body core protection. 

This John can be layered to increase the effective temperature range of your neoprene system. 

Here is a link with great information about layering, water temp recommendations, donning, care, etc.
 
Sizing information

Size Note there are no short and ling sizes and this is a short John.)

Prices (pre/post 8% tax)
JPY 31,000/33,480