The NEW Santi BZ420X Undersuit is the latest evolution of Santis best-selling BZ400X undersuit. It is now even warmer and more advanced!

Building on the success of the BZ400X, this new version is designed to offer even better insulation for the coldest and most demanding diving conditions. The Santi BZ420X Undersuit provides superior insulation, durability, and comfort, making it the ultimate choice for cold-water divers.

The BZ420X retains all the best features of the popular BZ400X: the signature elastic cuffs, inner suspenders, and convenient air flow ribbons for dry glove systems, ensuring full freedom of movement and ease of use during dives.

Upgraded Insulation

The Santi BZ420X continues to use the classic Thinsulate material, trusted for over 30 years in the diving industry. This time, Santi made it even better with enhanced thermal properties, offering superior warmth while maintaining its non-compressive nature underwater.

Thicker Polar Fleece

Santi has replaced the Micropolar from the BZ400 with a high-quality standard fleece Thermo Pile 100 for increased warmth and comfort. Designed for intensive wear, thermoactive and breathable fabric, giving freedom of movement.

Reinforced Design

Additional reinforcements with contrast material on the upper chest and shoulders ensure durability in areas prone to wear without sacrificing flexibility.

Modernised Aesthetics

The design has been refreshed, swapping the diamond quilting for a more modern “brick” pattern, offering a sleek, updated look that complements its superior performance.

Santi BZ420X features

• Two side pockets
• Inside pocket on the left chest,
• Reflective tapes
• Rubber thumb loops that supply air to dry gloves
• Elegant and comfortable collar
• Two-way zip
• In waist-elastic gusset
• Shoulder and knee gussets for free movement
• Grey inside suspenders
• Two p-valve openings
• One Heating opening
• Wide (10cm) elastic bands at the ankle to prevent the legs from riding up
• Comes with a durable bag

Santi BZ420X Specifications

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 Undersuit ordered, sculpting standard suits to a divers’ measurements.

With your undersuit order, you can request up to 4 changes (ranging from 2 to 5 cm) to any of the standard size measurements listed under the 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.