Santi BZ400X Undersuit
Mens Santi BZ400X Undersuit
Mens Santi BZ400X Undersuit
Santi BZ400X Undersuit

Santi BZ400X Undersuit - Men's

Sale price£490.00

Santi has used the best materials, technologies and expertise to produce Santi BZ400X Undersuit with many features. It is designed for cold waters with temperatures less than 7°C making it also ideal for long deep diving with decompression.



Modifications to Size

Modifications to Size


Standard sizes dispatched in 1 to 2 days

Contact Form & Details

How can we help?

If you need to contact us for any issue or assistance, you can do so online by filling out the online Contact Form, emailing us at or calling us on +44(0)1305 824 555. If it's about a purchase you've made for us please also include your order number.

Our brick-and-mortar store Underwater Explorers based on Portland, Dorset is staffed 7 days a week, including weekends and bank holidays. As it's an active store visited by divers from around the country and world regularly, if we can't make it to the phone for any reason please leave a message and we'll get back to you asap.

Any queries are usually answered the very same day and at most within 24 hours.


Why Portland?

We’re located on the Isle of Portland (in Dorset) because Portland has been one of the most popular scuba diving locations in the United Kingdom even before we set up operations here back in the year 2000.

On one side, we’re minutes away from the sheltered waters of Portland Marina and Harbour, while on the other, it’s just a brief walk to reach our famous scuba diving destination Chesil Cove and start of the 16-mile-long Chesil Beach.  

Portland’s location makes it ideal for scuba diving, freediving, snorkelling and other surface water sports activities. 

Check out how many wrecks we have around here by clicking on Scimitar Diving's Wreck & Dive Sites chart!

Alongside dive clubs, many instructors and dive schools travel here to train and offer scuba diving certification ranging from open water diver to mixed-gas tech diving or rebreather diving levels.

Whether you’re doing a boat dive from Portland Marina or Castletown or a shore dive at Chesil Cove, Portland is well known for offering many possibilities: Reef diving to wreck diving and night diving, underwater photography or underwater videography. Anything other than cave diving is possible here.

Likely being the best-stocked diving shop in the UK, at Underwater Explorers we offer in-store scuba diving equipment advice and sales, as well as gas fills, to locals and visitors (read About Us).

But... If you’re googling “scuba diving shop near me” like some, look no further, there's DirDirect online.

Here at DirDirect, we list our cutting-edge equipment for worldwide delivery and we’ve got you covered whatever your level of diving: We’re your local dive store wherever you are in the world.

All that with over 20 years of experience especially in technical diving, from training to equipment, advice and sales.


Underwater Explorers, Unit 1, Maritime Business Centre
Mereside, Portland, Dorset, DT5 1FD


Men's Santi BZ400X Undersuit has all the solutions you need as a diver. Santi has used the best materials, technologies and expertise to produce this undersuit with many features.  BZ400X is designed for cold waters with temperatures less than 7°C making it also ideal for long deep diving with decompression.

With feminine details, the BZ400X is also available in a lady’s version, Santi BZ400X Ladies First.

Santi BZ400X Undersuit features

  • Breathable
  • Two side pockets
  • One inside pocket on the left chest
  • Reflective tapes
  • Thumb loops that supply air to dry gloves
  • Elegant and comfortable collar and yoke covered with softshell
  • Two-way zip
  • Reinforcing patches on knees, shoulders and back
  • In waist-elastic gusset made of windproof fabric
  • Shoulder and knee gussets allow free movement
  • Inside suspenders
  • Wide (10cm) elastic ankle bands prevent moving up the legs
  • P-valve and heating openings

BZ400X additional option

You can also request a name patch free of charge. Just let us know by equating for it at check out by writing it in the notes section.

Please note that once the order has been placed with Santi, this can no longer be added, so it’s important that you let us know when ordering.

Best thinsulate material

Santi has used the best materials and available technologies for the BZ400X undersuit.

The Thinsulate™ BZ400 Insulation, recommended by 3M, provides effective insulation, resistance to moisture and breathability. It is one of the best insulation which can be used in undersuits.

It is compressed, does not take up too much space under the drysuit, and does not restrict the diver’s movement.  It has a net layer, which makes the BZ400X even more durable and practically indestructible.

  • Thinsulate™ BZ400 Insulation
  • Lining: Micropolar weight 420g/m, warmth: 1.80 CLO
  • Outside layer: Polyamide, Polyester
  • Weight: 2.1kg

FREE "Made to Fit" service

Very few divers require a totally made to measure suit due to the wide range of standard sizes available from Santi Diving. With this in mind, Santi offers a free of charge Made-to-Fit service to any standard Santi BZ400X Undersuit ordered, sculpting standard suits to a divers' measurements.

With your BZ400X Undersuit order, you can request up to 4 changes (ranging from 2 to 5 cm) to any of the standard size measurements listed under chest, inner arm, biceps, forearm, waist, hips, inner leg, thigh, calf or body trunk on the Santi size chart.

If you would require more than 4 changes to make your suit perfect, you can add two more changes for a small additional charge.

SKU: 2003.XS