Santi Men's Undersuit BZ420X – Maximum Warmth and Mobility for Extreme Drysuit Diving

The Santi BZ420X is the latest and most advanced evolution of Santi’s legendary BZ400 series, now redesigned for increased thermal protection and diver mobility under a drysuit. With upgraded insulation, a reinforced fit, and improved ergonomic design, this undersuit is built for serious cold-water exposure. Whether you're conducting long deco stops or exploring freezing depths, the BZ420X is the ultimate thermal base layer for dry suit divers who refuse to compromise.

Key Features and Benefits

• Upgraded Insulation
  Enhanced core warmth and breathability - ideal for coldest water conditions under any drysuit.

• Reinforced Design
  Built for long-term durability and compression resistance, especially in high-movement areas like shoulders and knees.

• Enhanced Comfort and Functionality
  Elegant collar, thicker polar fleece, and ergonomic gussets ensure freedom of movement during gear-up and dive execution.

• Smart Undersuit Details
  Includes two side pockets, one interior chest pocket, thumb loops to aid dry glove inflation, and grey internal suspenders.

• Drysuit-Optimized Features
  Wide 10cm ankle bands prevent ride-up during suit donning. Dual P-valve ports and one heating connector opening offer full system compatibility.

• Safety and Visibility
  Reflective tapes improve visibility during surface operations or low-light conditions.

Detailed Description

Built from the inside out for serious drysuit divers, the Santi BZ420X redefines what a thermal undersuit can do. Starting with its upgraded insulation and thicker polar fleece interior, this undersuit retains core warmth while wicking moisture away from your skin. The shoulder and knee gussets ensure freedom of movement whether you’re climbing into a drysuit or deploying gear mid-dive.

Reinforcements in high-wear areas increase durability, while modernized aesthetics and reflective safety details make it equally functional above water. Its integrated rubber thumb loops serve a dual purpose - keeping sleeves in place and helping inflate dry gloves through the suit arms. Wide elastic ankle bands ensure a smooth donning process and prevent material bunching or discomfort.

The BZ420X undersuit also includes two side pockets and an interior chest pocket, giving divers convenient storage for gloves, caps, or small essentials. With specially designed ports for dual P-valve systems and heated connector access, it integrates seamlessly with drysuit accessories for long technical or expedition-style dives.

Weighing just 2.1 kg (men’s size L), the Santi BZ420X offers heavyweight warmth without unnecessary bulk.

Specifications

• Weight: 2.1 kg (Men’s L)

• Insulation: Upgraded, high-loft with thicker polar fleece

• Design Features:

  • Two side pockets

  • One inside chest pocket

  • Reflective tape

  • Rubber thumb loops

  • Elegant, comfort-fit collar

  • Grey inside suspenders

• Gussets: Shoulder, knee, and waist elastic gussets for full mobility

• Ankle Bands: 10 cm wide elastic to prevent undersuit ride-up

• Compatibility Ports: Two P-valve openings, one heating system port

• Zipper: Two-way front zipper

• Style: Modernized fit and finish for technical diving applications

Upgrade your thermal protection with the Santi Men's BZ420X Undersuit. Designed for serious drysuit divers facing extreme cold, this undersuit delivers unmatched warmth, mobility, and system compatibility. Choose the best for your dive - and stay warm from descent to deco.