Santi BZ420X Heated Undersuit

The Santi BZ420X Heated Undersuit represents an advanced evolution of Santi’s flagship model for drysuit diving. It provides unparalleled thermal comfort, even in extreme conditions, thanks to significant construction improvements. 

This heated undersuit protects the entire body by evenly warming the trunk, thighs, and arms. For the best results, you should wear it over a thin base layer to transfer heat directly to your skin. Consequently, you remain warm and comfortable underwater even if your battery power becomes low or completely drained.

Innovative Features and Design

Santi includes several upgrades in this version, such as a thicker inner layer for superior thermal insulation. This makes the BZ420X Heated significantly warmer than the previous BZ400 Extreme model. 

Furthermore, the new cable layout ensures more efficient heating and much better heat distribution across the body. The improved "brick" quilting pattern enhances flexibility while providing a more ergonomic fit. Additionally, the smooth inner material allows you to don and doff the suit with much greater ease.

System Requirements and Safety

To power the internal heating wires, use the Santi Drysuit Connector or Thermovalve 303. Santi offers three battery options: Battery 9Ah, Blue Power 14Ah and Blue Power 28Ah.

For the best results, wear a Santi heated undersuit over a thin thermal underlayer to direct heat toward your body safely. Additionally, a built-in safety switch prevents overheating and ensures a steady current flow.

Santi BZ420X Heated Undersuit Highlights

• Maximum heating temperature of 45°C with 110W of power.
• Heating elements positioned strategically on the torso, thighs, and arms.
• Thick inner layer (290g/m2) and robust outer layer (420g/m2).
• Offers approximately 3 hours of run time on a 28Ah battery.
• Includes integrated cables in the sleeves for easy heated glove connection.
• Features P-valve holes on both sides and water-resistant cuffs as standard.
• Ergonomic wiring allows for unrestricted movement and a natural body fit.
• Available in men's and women's sizes or a made-to-measure option.

Note: Batteries and connectors are not included and must be purchased separately. Never exceed 12V when operating this heating system.

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 BZ420X Heated Undersuit ordered, sculpting standard suits to a divers' measurements.

With your Santi BZ420X Heated 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.

Santi Heating Systems at glance

The Santi Heated BZ420X Undersuit has been designed as part of the Santi heating system, which currently includes items such as the Santi Heated Flex 2.0 Undersuit, Heated Vest Flex 2.0 and Heated Gloves.

Want to know which batteries can be used with Santi heating systems and decide which suits you best? Check out our Comprehensive Review of Batteries for SANTI Heating.

Read our SANTI Thermovalve and Drysuit Connector comparison.