Fourth Element's Halo A˚R Undersuit is made using highly advanced thermal technology and the most advanced materials and Fourth Elements genius body mapping system for the best protection. 

The Halo A˚R features the incredibly insulating material A°RGON™ in a compression resistant matrix, originally created for space exploration.  It has phenomenal insulation properties, enabling the Halo A˚R to achieve extreme thermal protection yet with a less bulky and less buoyant material. 

The outer layer of the thermals is waterproof offering excellent thermal protection even if your drysuit experiences leaks. This one piece suits has thumb and foot loops for easy of donning your drysuit, convenient two way zipper, and zippered pocket.