Very few products marketed to hunters provide what is arguably the single most important factor that contributes to success—more time in the field. A selection of extreme-cold-weather “body suits,” however, delivers on the promise of comfort, functionality, and warmth—everything a late-season hunter needs to endure extra hours on stand in brutal weather. We tested two of the best last winter while hunting whitetails on the coldest days of the season in northern Michigan and coyotes on frigid February nights. Pictured: IWOM XT, left; Heater Body Suit, right.

Comfort: Both garments provided equal degrees of warmth with mid-weight “fall” layers underneath. As we hunted in driving snow and windy, sub-zero conditions, the inside temp of both suits never dipped below 72 degrees. But since the Heater Body Suit has to be unzipped to glass, call, or shoot (see below), all that precious heat escapes.
Edge: IWOM XT
 
Mobility: The Heater Body Suit is easier to move around in before the shot, but the IWOM doesn’t have to be unzipped at the moment of truth. The hunter’s hands and arms are contained within the Heater Body Suit—a problematic constraint when game appears without warning.
Edge: IWOM XT

Packability: The IWOM can be rolled up, stowed, and toted fanny-pack-style to the stand, but the narrow waist strap allows the garment to flop around, loosening the strap. It’s easier to transport it by wearing it, but if you’re covering long distances, the parka-like bulk can cause overheating. The Heater Body Suit rolls up and is contained in straps that you wear like a backpack.
Edge: Heater Body Suit

Functionality: Due to the suits’ bulk, you should practice shooting in both (especially with a bow) before heading into the field. The Heater Body Suit, which comes with a safety harness (the IWOM features an opening for your harness tether), must be donned once you get into your stand, so expect to practice this maneuver, too. 
Edge: IWOM XT

Accessories: The Heater Body Suit doesn’t come with a hood, as the IWOM does, but does have a lot of nice extras. In addition to the safety harness, it features waterproof booties, a zip-on blaze orange overlay, and snow- and waterfowl-camo overalls for hunting in a variety of environments.
Edge: Heater Body Suit

Value: Both garments feature durable zippers, heavy-duty stitching, and quality buckles. But the Heater Body Suit has fewer seams and zippers, and therefore fewer features that might fail. The Heater Body Suit, made in the U.S., is cheaper off the rack, too.
Edge: Heater Body Suit

Versatility: The IWOM is waterproof; the Heater Body Suit is water-resistant. When moving between multiple predator stands or when hunting any game that could appear suddenly and allow only a fleeting chance at a well-placed shot, the freedom of movement afforded by the IWOM is hard to beat.
Edge: IWOM XT

Winner: IWOM XT (4 to 3)

IWOM XT
Price: $399Zip-off hoodIntegrated face mask
Built-in hand warmer
Waterproof
Windproof Polyester brushed-tricot shell with 120g (arms)/150g (body) of 3M Thinsulate insulation

Heater Body Suit
Price: 340-$350
Carrying strap
Safety harness
Water-resistant
Windproof
Polyester brushed-tricot shell with 300g of 3M Thinsulate insulation