Icebreaker
Icebreaker 200 Oasis Long Sleeve Half Zip (men's, size M)
- Weight: 1/10 How much it adds to your pack.
- Warmth: 7/10 How much the fabric insulates next to your skin. Heavier fabric is warmer and slower to dry.
Year-round layering on hill days: Icebreaker's most versatile midweight merino
- Weight
- 337 g (M)
- Fabric weight
- 200 g/m²
- Fibre
- Merino
- Merino
- 100%
Where to buy
Alpinetrek £83.56 In stock. Black or Dark Loden, size M in stock (Gritstone Heather £94.95, the list price). Free delivery from £85; the cost under £85 is not on the page.
View at shop: AlpinetrekIcebreaker £94.99 In stock. Free delivery. Gritstone Heather, size M in stock. Free standard shipping over £40; free returns.
View at shop: IcebreakerTiso £95 In stock. Free delivery. Navy. All five sizes listed are in stock. Free delivery over £50.
View at shop: TisoPrices checked 8 Nov 2026 on each shop's own page; shops can change them. We earn no commission on these links; shops are listed by price. More
Our ratings (out of 10)
1 to 10, compared with the whole market. Each says what it's based on. How we score
Weight
Estimate from maker's specs: the maker's weight 1/10How much it adds to your pack. 1: A real weak point.
Estimate from maker's specs
Warmth
From maker's figures 7/10How much the fabric insulates next to your skin. Heavier fabric is warmer and slower to dry. 7: Better than most.
200 g/m² is in the 190–239 g/m² band. The figure is the number in the name: Alpinetrek lists a material thickness of 18.9 micron, 200 g/m², and Icebreaker's guide calls around 200 g/m² midweight.
In short
Good for
- Year-round layering on hill days: Icebreaker's most versatile midweight merino
- Cool-weather hiking and winter days under a shell, with a zip to vent heat
- Walkers who want a 100% merino top with a neck zip that is warm but not a heavyweight
Strengths
- 100% merino wool, 200 g/m² midweight fabric
- Half-length front zip to adjust ventilation and cover the neck
- Gusseted underarms, offset shoulder seams and flatlock seams to reduce friction under rucksack straps; drop tail hem for coverage
- Soft with no itch in all three sources: two tests and Icebreaker UK's customer reviews
Weaknesses
- The published weight for size M (337 g) looks too high next to the 242 g MyTrails weighed, so we don't score weight
- Merino dries slower than synthetic (Test 4 Outside)
- Icebreaker calls the fit slim but MyTrails and Test 4 Outside found it regular to relaxed: size by trying on
- Only two independent tests of this half zip found, none on long-term durability
- Machine wash cold on a gentle cycle with the zip closed; Icebreaker says do not tumble dry
Sources
We haven't tested this ourselves. Every score comes from these specs, tests and reviews.
ShowHide sources (7)
- Icebreaker UK: Men's 200 Oasis Half Zip Thermal Top: price £94.99, weight size M 337 g (looks too high), 100% merino
- Tiso: Icebreaker Men's 200 Oasis Long-Sleeve 1/2 Zip Thermal Top, Navy (price, sizes, weight size M 337 g, as Icebreaker UK)
- Alpinetrek: Icebreaker 200 Oasis L/S Half Zip (material thickness 18.9 micron, 200 g/m², price)
- MyTrails: Test of the Merino 200 Oasis Base Layer from icebreaker (men's half zip size M and women's size S, Dolomites; men's M weighed 242 g)
- Icebreaker: base layer guide (lightweight layers 75–175 g/m², midweight around 200 g/m², heavyweight 260 g/m² and above)
- Test 4 Outside: Icebreaker Men Merino 200 Oasis LS Half Zip (tested at the UTMB shoot in snow and rain)
- Icebreaker UK customer reviews: Men's 200 Oasis Half Zip (20 reviews, 4.7 out of 5; shop reviews count once)