DownUnder™ Merino Mid Bottom

ITEM # PG-10431

Regular Price: $99.95

Special Price: $24.97

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    Regular Price: $99.95

    Special Price: $24.97

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  • downunder-merino-mid-bottom-black -base-layer
  • downunder-merino-mid-bottom-black -base-layer


Your fix for bipolar weather comes in the form of Simms’ Merino Mid Bottoms, featuring prime under-wader performance via nature’s top temperature regulator. Merino Wool delivers itch-free living with an uncommon warmth-to-weight ratio achieved by small fibers that trap body heat, while banishing moisture into the atmospheric ether. Flatlock stitching equals intuitive stretch and recovery for deft moves over, around, under, and through widespread river obstacles. And source flat-seam construction for a finish so smooth your skin will thank you for more time spent fishing.


  • Warmer, 18.5 micron, 260gm unbleached Merino wool with softer hand for the best warmth and moisture management
  • Flat seam construction
  • Flatlock stitch stitch provides great natural stretch & recovery
  • Natural fiber is odor resistant
  • Fabric Tech: 100% Merino Wool
  • Approx Weight: 10 oz./260 g/m2
  • Sizes: S/20, M/30, L/40, XL/50, XXL/60
  • Sizes: S–XXL


Product Care

Merino Wool Product Care

Machine-wash cold, tumble dry low. Fabric softeners not recommended.

Flipping items inside out when washing can prolong the look and feel of the fabric.



  • Merino wool is exceptional for performance outdoor wear because the fabric is excellent at regulating body temperature by keeping you warm on cold days and cooler on warm days. It has an excellent warmth-to-weight ratio compared to other wools, in part because the smaller fibers trap body heat. It draws moisture (sweat) away from the skin to provide excellent moisture management, the wool fiber absorbs and releases 10X the moisture of synthetic fibers. The extrafine fibers of Merino wool offer comfortable, no shrink next-to-skin layering without itch or odor.


Customer Reviews

2 Review(s)

2 Item(s)

Treat yourself to a pair of these! Review by J Heames
If you don't own a merino wool base layer, treat yourself to a set! You will find that they have a much greater range of temperature regulation than your synthetics, I wear mine from 75 degree summer days to days where the high is 35. Odor control is remarkable and these can be worn for days on end. When you finally decide to wash them it won't be because they smell badly, which is saying quite a lot for a base underwear layer!

(Posted on 5/2/14)

Best mid weight bottom Review by Eugene Shuler
Guiding in the Smoky Mountains of North Carolina and Tennessee you need gear that holds up to harsh damp environments. You also need something that can still keep you warm if you take that unexpected plunge. The mountains here get just as cold as western states, except we have more humidity which makes every day seem damp and even colder. Dressing layers is the only way to stay warm. This is by far the best against skin layer you can buy. I also like the fact the wool comes from Montana farms. We believe in buying made in the USA products and like them even better when the materials are coming from the US too. Great job Simms!

(Posted on 3/27/14)

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