I just recently bought this top to replace a similar style synthetic one. The difference is night and day! I was getting hot, sweaty and itchy under the synthetics on long hikes. The merino fabric feels so much nicer on my skin and breathes so well, the comfort levels have improved 10 fold! Also love the zip for chest cooling and the thumb loops to protect the backs of my hands from the sun. Well done IO 👏🏼

I always thought that the only big brands could make good quality products but I was wrong. Anything I have purchased from IO Merino so far (almost all my fitness gear) is of very very high quality. This long sleeve Ultra Zip is all you need apart from the sleeveless IO merino's tshirt on a cool morning when you are out for a run. I am 185cms tall and wear medium size clothing from IO. Again it's made way better than any big brand you could think of and looks smart.

long sleeved t-shirt fits perfectly, is worn most of the time other than warm weather, perfect for my long distance hiking expeditions.
I have had probably 3-4 of these, that's how much I like them. Always the same, grey, colour. Just wish I could find another colour that I would like.

Very light weight but with high neck zip keeps all body heat in very efficiently. Impressive winter layer
always high quality from IO-Merino

Fantastic shirt, worked really well in cool to cold conditions. Fit was pretty true I think.

I own 3 of these tops now. 1 x for good, 1 x for home and 1 x well worn old job for camping/fishing. They are precious when new but better as they age and I care less about the nicks and holes. Perfect around home, brilliant out on the trails, up the river or at the cricket etc in the mid seasons. Always my go to option for comfort and transition warmth. I can wear this excellent top for a few days before a wash when out and about which I wouldn't do with a synthetic. Cheers R.

The fit is fantastic, and so comfortable to run in. Perfect for the cold dark morning starts, yet breathes so well once I get into my stride and heat up. Ultra satisfied with this next ioMerino product, you guys keep delivering the good stuff!

Very comfy & great fit, warm too

This is my second order of Ultra Zips. They are great - warm and comfortable, and even stay warm when the rain comes unexpectedly. Highly recommended.

Bought the Ultra Zip in Grey and I absolutely love it. This is my first IOMerino product and I’m really impressed by the quality. Feels soft, it’s super warm and fits really well. On the fit, I’m 5,11 (180cm) 75kg athletic build and while the medium fit was perfect across the shoulders, it would ride up if I put my hands up and was just a bit too tight to be comfortable for running and layering when climbing/mountaineering. I sized up to a large and it’s perfect.

Highly recommend this.

My 5th or 6th IO top. Brilliant layering, easily packed for outdoor adventures and good enough for the pub. Can't fault ordering, sizing or delivery.

Ultra Zip my second long sleeve IO shirt. Great quality and fit. Would definitely recommend.

Perfect winter running top. super comfortable under a pack, nice snug size, and the right length hem, not annoyingly long like other brands

So liked my ultra zip when it arrived I immediately ordered a second. The fact they are being made by the lovely Fijians unlike that famous New Zealand brand which has shifted all production to a Marxist dictatorship with an appalling human rights record is a real bonus.

I bought this for summer bike riding. Wonderful comfortable, light weight and the long sleeves give my arms protection from the sun. First time I have used thumb holes. Recommended.

Great fit and quality. Good to wear on a run or hike, and also as an every day top

Bought this for my hubby for fathers day and it's been worn non stop since. Love the silver pine colour, it is so versatile and something a bit different from the standard navy or black that most merino wool products for men come in. Great quality product and true to size.

Good top, but not as good as the Attitude Zip top as in I went a size down from 2XL to XL so it was a nice tight fit but the arms are a bit shorter and the thumb hole is in a slightly different position and size, but absolutely love the lighter colour to reduce heat buildup, why can’t they just add this colour and maybe a lighter grey to the Attitude Zip range then it would be a ***** instead of a **** rating.

The Ultra Zip has the best all around fit for comfort, function, performance and durability that I have found when compared to other brands and styles of wool tops. I found that the true to size recommendation is spot on. I typically wear a medium shirt and the medium fits great. Approx. 5'10", 40" chest, 33" waist. If you are like me and don't like garments that are too snug around the arm pits then you will love the Ultra zip. Even when I put my work shirt over the Ultra I don't get bunching or that restricted feeling under the arm pit. It still has a mild form fitment that tends to lay on the body but doesn't squeeze the body so it is not restrictive in any way. This perfect balance between fitment and comfort will allow you to wear the Ultra Zip as a base layer if you like and still allow full range of motion under casual or more dressy shirts as well as any other type of mid layer without bunching or discomfort of any kind, even when wearing a cotton shirt or fleece jacket over the Ultra. The Ultra's fabric weight of 160 GSM has the best balance of temperature regulation and warmth to weight ratio for my body's temperature temperament. I get cold easy but when I start to heat up the heat builds fast. I need a comfortable lightweight layer that reasonably resists the cool and breaths fast when needed; io did just that with the Ultra. I love how the superfine wool resist heat loss when mostly static but once you start to heat up it allows quick ventilation. The sleeves can also be worn comfortably when pushed up the arm past the elbow due to the really good stretch that the elastane offers and it has no issues repeatedly returning back to its original shape after the garment has been stretched. It is absolutely true that lightweight wool of this nature will benefit from the addition of a small percentage of nylon. I encourage you to look up all the benefits. No need for me to bore ya in this review but suffice it to say that while the site does mention you can poke your finger through the wool especially when wet (listed in io's section of top 7 things of What Not To Do) if you're not careful, when nylon is added to the fabric recipe it exponentially reduces accidents like this from happening. Nylon is also less prone to shrinking so if you do need to throw the Ultra in the dryer on low or very low heat it helps to resist any heat related shrinkage. I have thrown the Ultra in the dryer many times with perfect success but I don't let the dryer completely dry out the fabric. I use this same principal on many of my cloths and all of my wool garments with no negative issues to date and I have been doing this for over 20 years with perfect success; but, your specific conditions and equipment's ability to maintain proper temperature reliably could differ. If you choose to use the dryer, I highly advise to check your dryer very often until you are 100% confident and familiar with your equipments performance to ensure no over drying of the fabric occurs. From daily wear, athletic activities to cozy bed time comfort, I have not yet found a limit for the Ultra. The Ultra Zip may just be the Ultimate all around versatile and cozy top you can find. :O) I highly recommend this product.

A nice pullover, fit is a tiny bit small for the XL that I purchased. But once I started working out, didn't notice. The quality is very nice

Purchased for sons outdoor Ed camp- warm, doesn’t smell, lightweight, functional- perfect boy clothing!

i don't often shop online but I have found ioMerino products great and have had no problems with delivery.

Perfect for golf on the cool mornings of autumn and spring. Comfortable without restricting movement.
Well designed, looks and feels great.

Purchased as a gift for my partner who was looking for a long sleeve light merino top with a collar for sun protection when cycling. The blue colour is great and the large size is a good relaxed fit, not too tight but not too baggy. He wore it on a 3 day bike tour without washing, I didn't notice any smell. It will be able to be used also for a number of activities like hiking and ski touring.

I have worn my Ultra Zip on four runs. The material relatively warm and dries quickly. It did not smell after I wore it three times without washing it. The material is non-itchy, relative to other wool products that I have tried.

The top has a slim fit, and seems designed to be worn either directly against the skin or above another shirt. When I wore this shirt directly against my skin, the shirt's zipper irritated the skin along my sternum. The irritation was minor, and my skin is quite sensitive. I tried the zipper in a couple positions, but the irritation persisted. As a result, I prefer to wear this top over another shit.

The ‘long’ sleeves & polo neck are great, Like the fact it available in burgundy colour (not ‘loud’). Very good design. These are my daily wear. Yes, i would be happy to renew when the time comes😁. MS

This is the second top I have purchased as its beats other brands for softness and a high warmth to weight ratio. Perfect fit.

Great base layer for hiking. Tried a lot of different brands of pure merino and always found that they were itchy. Have worn the Ultra Zip several times now in wet weather conditions and it's very comfy, no itch. Would purchase again for sure.

Great feel, weight (for Southern California), and color (Dazzling Blue). MInor suggestion: cut a tad too slim for my taste (6', 170 lbs.). I would have preferred a regular cut option.