Pro Flex Thermal Baselayer Top: Heather Shadow from BN3TH Underwear
Pro Flex Thermal Baselayer Top: Heather Shadow from BN3TH Underwear
Pro Flex Thermal Baselayer Top: Heather Shadow from BN3TH Underwear
Pro Flex Thermal Baselayer Top: Heather Shadow from BN3TH Underwear
Pro Flex Thermal Baselayer Top: Heather Shadow from BN3TH Underwear
Pro Flex Thermal Baselayer Top: Heather Shadow from BN3TH Underwear
Pro Flex Thermal Baselayer Top: Heather Shadow from BN3TH Underwear
Pro Flex Thermal Baselayer Top: Heather Shadow from BN3TH Underwear
Pro Flex Thermal Baselayer Top: Heather Shadow from BN3TH Underwear
Pro Flex Thermal Baselayer Top: Heather Shadow from BN3TH Underwear
Pro Flex Thermal Baselayer Top: Heather Shadow from BN3TH Underwear
Pro Flex Thermal Baselayer Top: Heather Shadow from BN3TH Underwear
Tap to zoom

Pro Flex Thermal Top

Heather Shadow

Mid-Weight Warmth. Ultra-Soft Cold Weather Comfort.

$70.00 CAD

Color:  2 Colors
Size:

Size Guide



Built for cold days in motion, the Flex Thermal baselayer delivers the warmth you need without sacrificing breathability or mobility. The ultra-soft brushed fabric feels comfortable next-to-skin while managing moisture to keep you dry during activity. With stretch built in and a engineered fit designed for layering, it moves naturally with your body whether you're outdoors, training, or navigating cold-weather days.

Fabric: 88% Recycled Polyester, 12% Spandex

The brushed recycled polyester interior provides soft warmth and moisture management, while spandex delivers high stretch, recovery, and support.

SHORT FEATURES

Mid-Level Warmth
Ultra-Soft Brushed Fabric
4-Way Stretch & Support
Moisture Wicking & Quick-Drying
Breathable
Gusset for Enhanced Mobility
Ionic+® Anti-Odour Technology
Chafe-Free Flatlock Stitching

This baselayer top has a next-to-skin fit.

  • Machine wash cold
  • Do not bleach
  • Tumble dry low
  • Do not iron
  • Do not dry clean

View Size Guide

All BN3TH fabrics are soft and made from a performance stretch fabric. If your measurements are between sizes, select a larger size for a looser fit or a smaller size for a tighter fit.

files/2023-08-31-fit-and-function-pro_a113c8b9-1052-4de8-a34b-5ab463503246.svg

Free standard shipping is available on all orders above $75 (after discounts and before taxes).

All available shipping options will be visible at checkout. We ship orders within 1-2 business days, but this can increase during promotional periods.

Returns or exchanges will be processed up until January 31, 2026 for items purchased at a discount of less than 30% between November 8 and December 26, 2025. Products discounted by 31% or more will be final sale. For more information, check out our Frequently Asked Questions page.

Mid-weight warmth, stretch, and breathable comfort. Built for cold weather layering.
MID LEVEL WARMTH
MID LEVEL WARMTH

Warmth

MOISTURE WICKING
MOISTURE WICKING

Stay Dry

IONIC+® ANTI-ODOUR
IONIC+® ANTI-ODOUR

No Stink

FLATLOCK STITICH
FLATLOCK STITICH

Chafe-Free

Features That Perform

HYBRID RAGLAN

Engineered with a hybrid raglan-back and front tailored cap sleeve construction to enhance shoulder mobility and allow for unrestricted movement.

UNDERARM GUSSET

A gusset extends under the arm to enhance mobility, reduce friction, creating an unrestricted fit.

BRUSHED WARMTH

Brushed 4-way stretch fabric creates a soft next-to-skin feel while helping trap warmth for comfortable cold-weather wear.

ENGINEERED COMFORT

WHY WE MADE THIS

We built this baselayer to do more than just keep you warm. We designed Pro Flex Thermal top and bottom to balance support, breathability, and freedom of movement, using brushed recycled fabric that feels soft against the skin and performs when your day picks up. It’s the layer you start with when the temperature drops.

SUSTAINABILITY MATTERS

Made with post-consumer recycled polyester fabric and elastic, this product is certified to the Global Recycled Standard (GRS).
OEKO-TEX® certified fabrics guarantee that our end products are tested and proven free from harmful toxic chemicals.