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Long Sleeve Underwear
(201 products)Products (201)
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- IcebreakerMerino 200 Oasis Long-Sleeve Crewe Thermal Top - Men'sTop Rated$78.73Save 25%compared to  $105.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:LightweightSize Type:Big, RegularREI OUTLET
- Terramar2.0 Cloud Nine Midweight Performance Thermal Turtleneck - Women's$32.73Save 31%compared to  $48.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:MidweightSize Type:RegularREI OUTLET
- SpraywayEffra Jacket Base Layer Top - Women's$46.73Save 28%compared to  $64.95Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:HeavyweightSize Type:Regular, PlusREI OUTLET
- Kari TraaAlma Hood Base Layer Top - Women's$59.73Save 25%compared to  $80.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:UltralightweightSize Type:RegularREI OUTLET
- Kari TraaLune Long-Sleeve Base Layer Top - Women's$41.73Save 35%compared to  $65.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:HeavyweightSize Type:RegularREI OUTLET
- SeirusHeatwave All Season Reversible Long-Sleeve Base Layer Top - Women's$36.83Save 50%compared to  $75.00Underwear Weight:LightweightSize Type:Regular
- Kari TraaMalia Long-Sleeve Base Layer Top - Women's$52.73Save 24%compared to  $70.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:MidweightSize Type:Regular, PlusREI OUTLET
- IcebreakerMerino 260 Tech Long-Sleeve Half-Zip Thermal Base Layer Top - Kids'$52.73Save 29%compared to  $75.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:MidweightSize Type:RegularREI OUTLET
- Ortovox230 Competition Zip-Neck Base Layer Top - Men's$120.00Underwear Weight:MidweightSize Type:Regular, Big
- ArtilectGoldhill 125 Zoned Crew Base Layer Top - Men's$79.73Save 38%compared to  $130.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:LightweightSize Type:Regular, BigREI OUTLET
- Ortovox120 Comp Light Base Layer Hoody - Men's$120.00Underwear Weight:LightweightSize Type:Regular
- Terramar3.0 Thermawool Half-Zip Base Layer Top - Women's$56.73Save 24%compared to  $75.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:MidweightSize Type:RegularREI OUTLET
- IcebreakerMerino 200 Sonebula Long-Sleeve Crewe Base Layer Top - Men'sTop Rated$89.73Save 25%compared to  $120.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:MidweightSize Type:Regular, BigREI OUTLET
- Icebreaker125 ZoneKnit Long-Sleeve Crewe Base Layer Thermal Top - Women's$93.73Save 25%compared to  $125.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:LightweightSize Type:RegularREI OUTLET
- IcebreakerMerino 200 Sonebula Long-Sleeve High-Neck Base Layer Top - Men's$93.73Save 25%compared to  $125.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:MidweightSize Type:RegularREI OUTLET
- Arc'teryxRho Heavyweight Zip-Neck Base Layer Top - Men's$112.73Save 19%compared to  $140.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:HeavyweightSize Type:BigREI OUTLET
- Sweaty BettyHigh-Neck Jacquard Base Layer Top - Women'sTop Rated$82.73Save 29%compared to  $118.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:MidweightSize Type:RegularREI OUTLET
- Kari TraaRose Light Half-Zip Base Layer Top - Women's$89.73Save 25%compared to  $120.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:MidweightSize Type:RegularREI OUTLET
- Free CountryMicrotech Heat Cocaber Base Layer Top - Women's$34.73Save 30%compared to  $50.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:LightweightSize Type:RegularREI OUTLET
- NRSH2Core Lightweight Union Suit - Men's$109.95Underwear Weight:LightweightSize Type:Regular
- Ortovox230 Competition Long-Sleeve Base Layer Top - Men's$110.00Underwear Weight:MidweightSize Type:Regular, Big
- ArtilectBoulder 125 Crew Long-Sleeve Base Layer Top - Women's$75.73Save 36%compared to  $120.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:LightweightSize Type:RegularREI OUTLET
- Icebreaker125 ZoneKnit Merino Long-Sleeve Crewe Thermal Top - Men'sTop Rated$93.73Save 25%compared to  $125.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:UltralightweightSize Type:Regular, BigREI OUTLET
- CotopaxiLiso Base Layer Top - Men'sTop Rated$44.73Save 31%compared to  $65.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:MidweightSize Type:BigREI OUTLET
- ArtilectDarkhorse 185 Zoned Crew Base Layer Top - Men'sTop Rated$109.73Save 31%compared to  $160.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:MidweightSize Type:Regular, BigREI OUTLET
- Icebreaker200 Oasis Sonebula Long-Sleeve Crewe Base Layer Top - Women's$89.73Save 25%compared to  $120.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:LightweightSize Type:RegularREI OUTLET
- ArtilectFlatiron 185 Quarter-Zip Base Layer Top - Women's$99.73Save 37%compared to  $160.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:MidweightSize Type:RegularREI OUTLET
- Kari TraaVoss Cashmere Mix Half-Zip Base Layer Top - Women's$116.73Save 35%compared to  $180.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:MidweightSize Type:RegularREI OUTLET
- ArtilectFlatiron 185 Crew Base Layer Top - Men's$96.73 - $109.73Save 30% - 31%compared to  $140.00 - $160.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletUnderwear Weight:MidweightSize Type:Regular, BigREI OUTLET
- IcebreakerMerino 260 Vertex Long-Sleeve Half-Zip Herenga Base Layer Top - Women's$89.73Save 40%compared to  $150.00Members use code OUT4JUL25 for $20 off $100+ at REI OutletSize Type:RegularREI OUTLET
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