Santi BZ400X Extreme Undergarment

The BZ400X Undersuit comes with a modern and fit cut with the highest thermal protection available.


Classic yet top of the list diving undersuit with the highest thermal protection available on the market. The BZ400X comes with modern and fit cut to increase your diving comfort and good looks. Dedicated for cold waters with less than 7°C temperature, it is ideal and unreplaceable for long deep diving, with decompression. Low water absorbing, high breathability features. Keeps a diver warm even if wet.

Thinsulate™ BZ400 insulation is recommended by 3M as optimal for diving undersuits due to its thermal features and pre-compressed insulation.

Lining made of soft microfleece 140 g/m2. The outside layer made of Polyamide additionally
reinforced with Polyester fabric in the areas exposed to mechanical damage.


  • Thinsulate™ BZ400 Insulation
  • weight 420 g/m2, warmth: 1,80 CLO
  • weight: 2,1 kg.


  • breathable insulation
  • two side pockets
  • one inside pocket on the left chest
  • reflective tapes
  • rubber thumb loops, that supply air to dry gloves
  • elegant and comfort collar
  • two-way zip
  • reinforcing patches on knees, shoulders and back
  • in waist-elastic gusset made of windproof fabric
  • shoulder and knee gussets allowing free movement
  • inside suspenders
  • wide-elastic ankle bands
  • specially designed p-valve and heating openings

See the size chart here.