Patagonia Micro Puff Pants

These are insulated puffy shell pants. They're best used standing still or for light walking; they're too warm for any kind of hiking or climbing. Patagonia no longer sells this exact product; Patagonia's similar product today is the DAS Light Belay pants. These are mostly well-designed as belay pants, except that the waistband's elastic and limited adjustment means they're best used with clip-on suspenders.

January 2025 Update: I've used these pants for winter trips and occasional local use in the DC metro for over a decade now. Adding some photos to provide better information, as well as some observations. If you want warm belay pants from Patagonia today, look at the DAS Light Belay Pants—very similar features to these pants. They've proved to be quite durable, though as belay pants, I've mostly worn them on extended stops and in camp, not climbing. 

With a spate of days/nights in the single digits and low teens lately, I've been wearing them to hang outside with the dog when she's running with other dogs on a field, and I'm standing still and getting cold. 

Original review:

Heaters. These are shell pants with synthetic insulation, Primaloft or some equivalent. They have a fairly loose fit. The waist adjusts via velcro tabs at each hip. They zip all the way up and down the side of each leg, so they are very easy to take off and put on.

For me, these pants are too warm for any extended/strenuous use unless it's truly arctic outside. They are fabulous for standing still or being around camp when it's cold, or putting on if you have an extended stop. They are lightweight (they weigh 17-20 oz, depending on what size you wear), they stuff well, and they are happily simple.

p.s - The outer shell fabric is very lightweight nylon, so if you anticipate any significant abrasion, you're better off with a more burly pair of shell pants worn as the outer layer. Also, they aren't waterproof.  

Added observations: Aynthetic fill is, my opinion, the way to go for warm belay pants. Even mild walking around generates some heat and moisture, which isn't usually a beneficial situation for down insulation. This fill is now well over a decade old and still insulates extremely well. 

Fair warning—I paid $105 for these in 2012....but Patagonia's synthetic fill belay pants are priced close to $300 MSRP. Talk about inflation. 

Background

I've worn these pants for over 10 years of winter trips and occasional local use in very cold weather.

Love these pants. They are warm enough to keep you toasty into the teen and have full side zips to aid in ventilation and temp control. The synthetic insulation does great in damp clammy conditions. Only downside is the lack of any pockets, but I still won't go climbing without them.