Flexible Material With a 3-Layer Design

The material is soft, supple and fairly thin. So it may surprise to learn that it’s actually comprised of three different layers that are heat-pressed together: an inner grid-thermal layer to trap body heat, a middle layer that’s water resistant, and an outer layer that blocks wind.

Importantly, all three layers allow for multi-directional stretch, which makes Stage 3 and K2 so form-fitting and comfortable without the discomfort of traditional compression gear.

The entire K2 Thermal shirt uses this material. Stage 3 is designed for use with body armor and the core material is different so you don’t overheat in your armor. The Stage 3 core material is a moisture-wicking, polyester/spandex blend that does not include the inner thermal-grid layer.

To learn more now, please see our Equinoxx Stage 3 and K2 Thermal product pages.

In Factoid #1, we discussed how Stage 3 (for wearing body armor) and K2 Thermal (full protection of the core for not wearing body armor) really do keep you warm, with a temperature rating of 15 degrees fahrenheit (-9.45 degrees celsius). But these relatively thin base-layer shirts are also highly effective at blocking wind and resisting rain.

Customers say:

The first day that I tried it, the temperature was 16F with 15mph winds. I had on a cheap $10 base layer, the equinox over that, and a thin summertime FR shirt over the equinox. I DID NOT FEEL THE COLD NOR THE WIND AT ALL!!! —Mario Jimenez

Perfection. Used it in 28 degree weather with windy conditions and never felt the wind and was warm for my 8 hour shift outdoors. Best of all I didn't need to layer up and only had my long sleeve uniform shirt on and no bulkiness of having a jacket on. Great product. —Marco B.

I recently shared how I created Equinoxx Stage 3 thermal base-layer shirt as a police officer trying to stay warm in harsh winter weather without sacrificing my safety by wearing a bulky winter coat. And I’ve discussed some of the specific challenges police officers in particular face working in cold weather.

For many years now, Stage 3 has been highly popular with police, who wear it under their body armor, but also with others who use it for outside work and leisure activities in the cold. See their reviews on our Equinoxx Stage 3 product page. Some highlights:

Keeps You Both Warm and Mobile

“I work in WI so I need to be warm in the winter,” says Lina E. “I do not like to wear a coat, as I personally feel it is hard to get to my gear. This is PERFECT! I stay warm but I am not sweating under my vest. LOVE IT!!”

The cold weather will be here before you know it. And we need to tell you about the launch of an exciting new product from 221B that's going to be a complete game-changer for those working outdoors in the winter or those taking part in cold-weather activities. 

Called "Equinoxx K2 Thermal," it's a shirt that'll keep you warm and comfortable in the harshest weather—cold, windy, even wet—and also allow you unrestricted freedom of movement to perform at your best at work or play. 

The K2 shirt is soft, stretchy and not bulky, promoting superior comfort and mobility. Yet it's constructed with a state-of-the-art heat-pressed, triple-layer fabric that provides highly effective thermal protection. It retains body heat and keeps out the cold, while allowing the body to breathe (it's even comfortable when you come out of the cold). It blocks wind and resists water.

Every year nearly 70,000 people go to the ER due to heat related ailments. On average, there are over 700 heat related deaths annually. As the temperatures rise with each passing week, staying cooler while outside becomes increasingly important. This is especially important to those of us who work outdoors.

As someone who studied Bio-Chemistry in university and graduated Pre-Med, I had a deeper understanding of human physiology than most other Police Officers I worked with. So I utilized this knowledge to learn ways to stay cooler and hydrated while working outside all day in beneath the scorching sun.

During my research (I'm a nerd and a lab geek so research is actually fun for me) I discovered many interesting statistics. I'll share some of them below as I outline how I managed to go 13 years working outside in the extreme heat and beating some of the most common heat related illnesses. 

Approximately 9,500 Americans are diagnosed with skin cancer every day.  When I first heard this statistic I couldn't believe it.  Most people are oblivious to this fact.  As someone who worked in the sun 13 hours daily as a Police Officer, I became concerned. (Yes ... people with dark skin get sunburned and skin diseases).

Many times my arms and the back of my neck got sun-burned. It was uncomfortably painful and dangerous to my health.

Skin cancer is a concern for anyone working in the sun during summer months.  (BTW:  You can 100% get sunburned during winter months too).

I would apply sun block on my arms, face and back of my neck prior to my shift.  But once I began sweating this was negated.  Reapplying during the shift was messy and typically didn't happen.  Many co-workers (who were all fair-skinned) had similar issues during summer.  Not only were they worried about sunburn (and an unsightly farmer's tan), they also feared  consequences from skin cancer.