Heavyweight 400 Men's Thermal Bottoms 100% Merino Wool
Measurements
Please note, measurements refer to body size, not garment dimensions, unless otherwise noted. Measurements are in inches.
Men's Clothing Size Chart
| Size | Chest (in) | Waist (in) | Sleeve Length (in) | Shirt Length (in) | Inseam (in) |
|---|---|---|---|---|---|
| XS | 33-35 | 24-27 | 30-31 | 25.5-26.5 | 25-27 |
| S | 35-38 | 28-30 | 31-32 | 26.5-27.5 | 28-30 |
| M | 39-41 | 31-33 | 32-33 | 27.5-28.5 | 29-32 |
| L | 42-45 | 34-36 | 33-34 | 28.5-29.5 | 32-34 |
| XL | 46-48 | 37-40 | 34-35 | 29.5-30.5 | 32-35 |
| XXL | 49-52 | 41-44 | 35-36 | 30.5-31.5 | 34-35 |
| XXXL | 52-54 | 45-49 | 36-37 | 31.5-32.5 | 34-36 |
Men's Big and Tall Clothing Size Chart
| Size | Chest (in) | Waist (in) | Sleeve Length (in) | Shirt Length (in) | Inseam (in) |
|---|---|---|---|---|---|
| MT | 39-41 | 31-33 | 35-36 | 30.5-31.5 | 32-34 |
| LT | 42-45 | 34-36 | 36-37 | 31.5-32.5 | 33-36 |
| XLT | 46-48 | 37-40 | 37-38 | 32.5-33.5 | 33-36 |
| 2XT | 49-52 | 41-44 | 38-39 | 33.5-34.5 | 34-36 |
| 3XT | 52-54 | 45-49 | 39-40 | 34.5-35.5 | 35-37 |
| 4X | 54-57 | 49-52 | 36-37 | 32.5-33.5 | 34-36 |
| 4XT | 54-57 | 49-52 | 40-41 | 35.5-36.5 | 35-37 |
| 5X | 57-59 | 52-54 | 36-37 | 33.5-34.5 | 34-36 |
| 6X | 59-61 | 54-56 | 37-38 | 34.5-35.5 | 34-36 |
How to Measure
Chest: Measure the circumference around the fullest part of your chest, underneath the arms.
Waist: Measure the circumference around the natural waist, near the belly button.
Sleeve: Measure from your center back neck, to the elbow, to the wrist.
Shirt Length: This measurement refers to the approximate size of the shirt back length, from the neck to the bottom hem.
Inseam: Measure from the center of the crotch to the end of the ankle.
Shop Men's Clothing Shop Men's Big and Tall Clothing
Fit Types
Athletic Fit |
Regular Fit |
Relaxed Fit |
 |
 |
 |
|
Fits best as: Base Layer Skin tight, slim, compression style fit. Wear this layer first and add on top of it if needed. |
Fits best as: Base Layer, Mid Layer True to size, standard fit with a little bit of room to breathe, but not too baggy. Perfect on its own or with a t-shirt or thin shirt underneath. |
Fits best as: Mid Layer, Insulating Layer, Outer Layer A little more room than you would find in a Regular fit. Enough space to fit 1-2 layers underneath. |
Fit FAQs
What if I am between sizes?
If you are between sizes, we recommend sizing up or down based on what fit type you would prefer, and based on how you plan to wear the piece. Our knitted merino is stretchy and you could realistically go with either size. If you would prefer an Athletic fit, size down. If you prefer a Regular or Relaxed fit, size up.
Do I need to size up/down to layer?
Generally, no, you do not need to purchase a different size than normal. Our base layers are designed to fit right into your current layering system. They are also designed to work with other products in our line, too. You may wish to adjust your sizing if you plan to wear one of our garments in a way that it is not intended, if that's the case please feel free to contact our customer service team for help.
Does your clothing run true to size?
Yes, our clothing runs true to size and is sized similar to most other American brands. If a sizing discrepancy is discovered, you will see fit advice in that product's specific listing.
Not sure what size or fit type you need?
Learn more about layering systems and how they can help you choose. Still need help? Contact our customer service team for personalized advice.
- In stock, ready to ship
This certified product has been tested against a list of over 1,000 harmful substances, including PFAS.
