Womens Thermal Underwear Bottoms - Diamondown

Women’s Thermal Underwear Bottoms maintain 91% of body heat and 40% of radiant body heat. Thin and light weight insulated long johns with moisture wicking capability. Patented revolutionary fiber blend fabric, traps your natural body heat to keep your warm and comfortable.

Diamondown™ cold climate clothing maintains twice the natural body heat compared to any other fiber keeping you warm and comfortable outdoors. Read more about our clothing’s patented technology here. Diamondown is made in America.


  • Proven in extreme conditions
  • Weight – 8 oz per square yard
  • Soft and comfortable
  • Machine wash and dry – will not shrink and long lasting
  • Color – medium gray
  • Sizes – S, M, L, XL, 2XL. View Sizing Chart
  • PLEASE NOTE TALL SIZES ARE SPECIAL ORDERS but we do our best to keep some in stock
  • Made in the USA

Clear selection

Women’s Thermal Underwear Bottoms maintain 91% of body heat and 40% of radiant body heat. Here are Actual Customer Comments: 

“Diamondown™ has become an indispensable part of our winter gear when venturing outdoors in Colorado during the winter.   

We are avid skiers and it can get really cold at 12,000 feet, especially when sitting in an open chair lift.  It is, quite frankly, our undergarment of choice not only when we ski, but anytime we are going to be spending any significant time outdoors during the winter, be it taking our Siberian Huskies for a romp, shoveling snow, or just going out for a walk.   

You have to wear this stuff to believe it.  Compared to other long underwear we have had, this stuff is so unbelievably comfortable and warm.  It is super lightweight, breathable and thin. You don’t even know you have it on, but then you suddenly realize how warm and comfortable you are without the sweat and itchiness of other products.   

Between the 4 of us we probably have 20 sets of Diamondown™.  The best way to describe it is high tech winter underwear.  It’s like making the temperature outside 20 degrees warmer.  Once you try it, you won’t want to be without it.”



2 XL, Large, Medium, Small, XL

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