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Santi BZ400X Standard Undergarment

4.9 from 1100+ reviews

$1,300.00

Free shipping on orders over $150
Local pickup available at Bondi store
30-day returns on unused items

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The layer that actually keeps you warm — not the shell
Loft matched to Sydney winter and to your suit
Heated options for long or deep dives
Fitted with your drysuit so nothing bunches or binds

Description

Classic diving undersuit with market-leading thermal protection. The BZ400X undersuit comes in a fitted cut to increase your diving comfort and appearance. Dedicated for cold waters less than 7°C, it is ideal and unreplaceable for long deep diving, with decompression. Low water absorbing, high breathability features. Keeps you warm even if wet.

Shipping

Free shipping on orders over $150. Local pickup available at Bondi Beach. International shipping calculated at checkout.

Returns

30-day return policy on unused items in original packaging. Custom-fitted gear is non-returnable.

Don't forget SANTI Bergen 2.0 - Merino Top Baselayer $240.00· Choose options

Your drysuit doesn't keep you warm — this does

A drysuit is a shell. What keeps you warm is the loft underneath it, and getting that layer right is the difference between enjoying a winter dive and counting down the minutes.

We stock the Santi and Fourth Element ranges we dive ourselves, from merino base layers through to heated systems for long decompression and rebreather dives. Thicker is not automatically better — an undergarment that's too bulky compresses, kills your fit and drives your weighting up.

Come in with your suit and we'll match it properly. It's a five-minute conversation that saves a lot of cold diving.

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4.9

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Frequently Asked Questions

Find answers to common questions about our gear, courses, and policies.

Which drysuits can I buy off the shelf?

The Avatar Airon and the Bare Aquatrek Evo are our off-the-shelf suits — you can be diving one straight away.

How long does a made-to-measure suit take?

It depends on the brand. Navyfel is about 4 weeks, Bare about 8, Santi 8 to 10, and Fourth Element around 16. If you have a trip booked, work backwards from that date and come and talk to us early.

Which drysuit should I go for?

It depends on the diving you want to do — cave, cold water and travel all pull in different directions on material, seals and pockets. Tell us what you want to use it for and we will tell you honestly which suit fits that.

Does the suit itself keep me warm?

No — the undergarment does. The suit is a shell that keeps water out; the loft underneath is what holds the heat. Getting that layer right matters as much as the suit, and bulkier is not automatically warmer.

Fast delivery and convenient online shop

Modern technologies and materials

Comfortable to use anytime

Flexible return policy and warranty