{
 "id": "rei-coop-midweight-half-zip-base-layer",
 "name": "REI Co-op Midweight Half-Zip Base Layer Top",
 "brand": {
  "name": "REI Co-op",
  "url": "https://agenticrecs.com/brands/rei-co-op/"
 },
 "model": "Midweight Half-Zip Base Layer Top",
 "department": {
  "id": "running",
  "name": "Running",
  "url": "https://agenticrecs.com/running/"
 },
 "category": {
  "id": "running-base-layers",
  "name": "Running base layers & tops",
  "url": "https://agenticrecs.com/running/base-layers/",
  "json_url": "https://agenticrecs.com/running/base-layers/index.json",
  "schema": "running-apparel"
 },
 "subtype": "budget synthetic thermal half-zip",
 "msrp_usd": 69.95,
 "msrp_note": "Men's list price on rei.com. OutdoorGearLab's women's Best Buy is a different item (REI Co-op Midweight Base Layer Crew, $65 in that review), not verified here.",
 "price_tier": "Budget",
 "price_checked": "2026-10-26",
 "attributes": {
  "fits": [
   "men"
  ],
  "warmth": "mid",
  "wind": "none",
  "water": "none",
  "visibility": "none",
  "temp_range_f": [
   25,
   45
  ],
  "temp_range_c": [
   -4,
   7
  ],
  "temp_basis": "estimate"
 },
 "awards": [
  {
   "label": "Best budget",
   "guide": "cold-weather-running",
   "chapter": "base-layers",
   "url": "https://agenticrecs.com/guides/cold-weather-running/base-layers/"
  }
 ],
 "summary": "The value pick: a soft, fast-drying synthetic half-zip that OutdoorGearLab rates a Best Buy, giving up some warmth compared with wool in exchange for a much lower price.",
 "best_for": "Runners on a budget who want one warm, quick-drying half-zip for roughly 25-45°F runs or for layering under a shell.",
 "not_for": "Runners who want merino's odor resistance for repeat wears or running-specific extras like reflective trim.",
 "downsides": [
  "Less warm than wool for its weight, per OutdoorGearLab",
  "Reviewer found it harder to layer than some rivals",
  "No odor-control or reflective details listed"
 ],
 "where_to_buy": [
  {
   "retailer": "REI Co-op",
   "url": "https://www.rei.com/product/C08396/rei-co-op-midweight-half-zip-base-layer-top-mens",
   "affiliate": false
  }
 ],
 "materials": "92% recycled polyester, 8% spandex; peached face fabric",
 "style_number": "C08396",
 "key_features": [
  "220 g/m² midweight stretch synthetic",
  "Peached fabric for a soft next-to-skin feel",
  "Half-zip front with high neck coverage",
  "Thumbholes",
  "Semifitted cut"
 ],
 "specs": {
  "Fabric weight": "220 g/m²",
  "Fit": "Semifitted",
  "Neck": "Half-zip, high neck",
  "Thumbholes": "Yes",
  "Odor control": "None stated"
 },
 "official_url": "https://www.rei.com/product/C08396/rei-co-op-midweight-half-zip-base-layer-top-mens",
 "sources": [
  {
   "publisher": "OutdoorGearLab",
   "title": "Best Base Layer (GearLab men's guide)",
   "url": "https://www.outdoorgearlab.com/topics/clothing-mens/best-base-layer",
   "date": "2026-04-01",
   "finding": "Gave the men's REI Co-op Midweight Half-Zip a Best Buy award (listed at $70, 220 g/m²), crediting quick drying, soft stretchy fabric, thumb loops and flatlock seams; marked it down for being less warm than wool and harder to layer."
  }
 ],
 "evidence": {
  "specs_from": "https://www.rei.com/product/C08396/rei-co-op-midweight-half-zip-base-layer-top-mens",
  "reviews_summarized": 1,
  "tested_by_site": false
 },
 "guides": [
  {
   "guide": "cold-weather-running",
   "chapter": "base-layers",
   "url": "https://agenticrecs.com/guides/cold-weather-running/base-layers/"
  }
 ],
 "last_verified": "2026-10-26",
 "url": "https://agenticrecs.com/products/rei-coop-midweight-half-zip-base-layer/",
 "markdown_url": "https://agenticrecs.com/products/rei-coop-midweight-half-zip-base-layer/index.md",
 "json_url": "https://agenticrecs.com/products/rei-coop-midweight-half-zip-base-layer/index.json"
}