Men's Midweight OG Long Sleeve Merino Wool Black Base Layer

The Midweight OG is the warmer, more substantial take on our trusted OG Long Sleeve. At 230gsm, it delivers dependable insulation for cold mornings and winter adventures without adding bulk. Built from 100% New Zealand merino and designed with the same coveted cut, this base layer keeps you moving—whether you’re logging miles on a frosty trail or cooling down after a chilly plunge.

Why this midweight OG stands out

• 230gsm 20-micron Merino from New Zealand — soft against the skin, itch-free, and engineered for a second-layer comfort over your tee.
• Midweight warmth, zero bulk—robust insulation that layers seamlessly under a shell or jacket without restricting movement.
• Breathable, moisture-wicking, odour-resistant—stays dry and comfortable during steady effort or variable workouts.
• Thermo-regulating—helps you stay warm in cold temps and adaptable when conditions shift.
• Built to move with you—stretch and recovery knit supports your range of motion, season after season.
• Versatile layering option—ideal as a standalone top in cool conditions or as a base layer under heavier outerwear.
• Designed in New Zealand, made in China or Fiji using NZ merino for a balance of craftsmanship and value.
• Easy care—machine wash cold on wool/delicate cycle; lay flat or air dry to extend its life.

Real-world use cases

This is the go-to midweight layer for athletes and outdoor enthusiasts who want reliable warmth without bulk. Use it for:

• Winter trail runs, brisk hikes, and early-morning workouts
• Post-swim sessions or cold plunges where you need fast, gentle warming
• Daily commutes in chilly climates or as a base layer under a shell for alpine conditions
• Layered setups for variable weather, ensuring comfort from sunup to sundown

Who this is for

Ideal for anyone who runs naturally cold, spends time outdoors in cool or fluctuating conditions, or simply wants a reliable, long-lasting merino base layer. If you value a soft-touch feel, temperature regulation, and a garment that performs across activities, the Midweight OG is designed for you.

Fabric & care

• Fabric: 100% Merino Wool, 230gsm
• Micron: 20
• Care: Machine wash cold on wool/delicate cycle with wool detergent. Lay flat or air dry.
• Origin: Made in China or Fiji using NZ merino

Brand promise: Merino 365 NZ

Born in New Zealand and tested by nature, Merino 365 NZ brings the finest merino wool into daily wear. We commit to natural comfort, performance, and durability—without synthetics or compromise—so you can rely on merino every day, 365 days a year.

Specs at a glance

• Category: Apparel & Accessories > Clothing > Men's Undergarments > Men's Long Johns
• Tags you’ll notice in search: Merino 365 NZ, Shopify Collective
• Care: Wool cycle, cold wash; lay flat to dry