BZ420X SANTI undersuit is the latest evolution of the best-selling BZ400X model, offering enhanced warmth and advanced performance for cold-water diving. Building on the proven success of its predecessor, the BZ420X delivers improved insulation and durability, making it suitable for the most demanding diving conditions.

Designed for extreme environments, this undersuit combines trusted materials with upgraded construction to maximise thermal efficiency, comfort, and mobility during extended and cold dives.

Key Features:

Upgraded insulation using Thinsulate™ material, trusted for over 30 years in the diving industry, now enhanced for superior thermal performance while remaining non-compressive underwater
Thicker inner layer with Thermo Pile 100 fleece, replacing the previous micropolar, providing increased warmth, breathability, and freedom of movement
Reinforced construction with contrast material on the upper chest and shoulders for improved durability in high-wear areas (men’s version includes side pockets)
Modernised design featuring a “brick” quilting pattern for a clean, contemporary appearance

Additional Features:

Two side pockets
One internal pocket on the left chest
Reflective tapes for visibility
Rubber thumb loops to assist airflow to dry gloves
Comfortable, ergonomic collar
Two-way zipper
Waist elastic gusset for improved fit
Shoulder and knee gussets for unrestricted movement
Grey internal suspenders
Wide (10 cm) elastic ankle bands to prevent leg ride-up when donning a drysuit
Dedicated openings for two P-valves and one heating system

Comfort & Practicality:

Retains key features from the BZ400X, including elastic cuffs, internal suspenders, and airflow ribbons for dry glove systems
Designed for extreme cold-water diving, including freezing conditions and extended decompression dives
Engineered for maximum warmth, comfort, and usability in demanding environments

Additional Details:

Includes a durable carry bag for transport and storage
Positioned as a premium thermal solution within the SANTI range, following the success of the Kango undersuit

Technical Specifications:

Insulation: Thinsulate™ BZ400 by 3M
Weight: 420 g/m²
Thermal rating: 1.80 CLO
Total weight: 2.1 kg

Inner layer: Thermo Pile fleece (100% polyester)
Grammage: 220 g/m²

Reinforcement material: 72% nylon, 14% polyester, 14% spandex (high abrasion, high tenacity, ripstop)
Grammage: 196 g/m²