I purchased Altitude Zip base layer to wear over my gym TShirts, first thing in the morning when it's too cold to go for a run with a sleeveless tshirt. It keeps the upper body warm, merino material feels great on the body (nice and soft). It also looks very stylish, I received a few compliments in the public. I now have two of these in two different colours. I am 185cms tall and wear medium size. Absolutely love it.

I bought two of these to alternate weekly on my winter bike commute to work. A few weeks in and the quality and comfort seems very good. Also pleased to be supporting Australian made with Australian wool.

This top is the best for winter in Lithgow NSW b mostly because of the high neck zip, which can help vent when exercising. The quality merino material, just the right weight for layering and the design is so comfortable. I went up a size, didn't want extra tight fit, this worked perfect.

It feels so soft and comfortable! Look forward to buying more merino.

Perfect for when riding my bike. Long sleeves are great for keeping the sun at bay. I find it breathes well and wicks very nicely. Highly recommended.

Have been a long time user of merino products from ioMerino right from the early days and I am so glad to see them hanging in there and providing updated fantastic clothing. I use the base and mid layers all year round for golf, walking and exercise. Wish I could buy more. I still have ioMerino shirts from over ten years ago - amazing stamina!

I find myself virtually living in it full time.

It's the best base layer I have, I've got several kinds but it's my favorite, I've bought two of them 10 years ago in Quebec. Unable to find any more, I made the purchase in Australia and I am still satisfied with the 2022 version.

Great product works well for sea kayaking

I have been wearing IoMerino for probably 15 years now, even going way when it IO BIO. The quality is top notch, and softer and better then the other top competitors. Unfortunately there isn't a Canadian distributor anymore, but that didn't stop me from still purchasing online and shipping here to Vancouver, Sizing is true .with the duty and taxes its a little more, but well worth it my opinion. The Altitude Zip is my favorite, it hugs the body so well, and regulates the heat, and colors are vibrant. During my winter rides when its down to 5c I wear the altitude, pinnacle Zip, and altitude neck tub with a high Vis wind stopping and its perfect. Overall I love the product line, and have many different pieces! The customer support is fantastic as well!

This is my second Altitude Zip. What I like: the soft feel, the fit, the high neck, a choice of colours, the quick delivery. It really has a remarkably soft feel, and I enjoy putting it one each time I wear it. I use it in combination with a roll neck jumper in cooler weather, and really appreciate the way the higher-than-average neck keeps me warm, and keeps the coarser wool of the jumper off my neck. I found it 'true to size', ie the 'Large' size fitted me as I expected. It was good to get some colour options, rather than black-or-nothing. I received the item a day or two after I placed the order (and the website was well organised). I can live without the thumb holes, but others will appreciate them, and they don't get in my way. A classy product, and recommendable!

Excellent quality and great fit. I really appreciate a company doing an XS size. I had a problem with my first purchase and IO were just brilliant with their customer service. Could not be faulted. I am a fan!

Soft merino, skin fitting with zip collar all add up to a great base layer garment. I wear it under my long cycling jersey and find its generously long in arms and torso.
I wonder if there is a heavier weight wool version?

Sometimes it’s hard to buy soft woollen outdoor gear; and in this case I was pleased at the softness. The fit is as described. I’m happy with it so I ordered another one.

I chose the Altitude Zip for the ability to regulate your body temperature. When going up and around mountains, particularly in the rainforest mountains of the Queensland/NSW border; you need to minimize your sweat; also, the colours highlight the billion-plus leeches, that love your blood as much as you do!
This top hugs your body like a baselayer should and with a Merino T-Shirt or tank underneath - you are set for a days hike with cool to moderately cold weather.

Loved mine so much I bought one for my husband. He loves it for riding and running. Great warmth when zipped up and hands covered, and great temperature control with zips down and hands exposed. Not scratchy or smelly. Can be used a number of times without washing which was great when we recently went away.

Soft, very light and warmer than a fleece. Just not bulky like other fabrics of the same warmth.
The thumb holes are great but dont get in the way if you dont use them.
I wear this with a merino base layer and a shell jacket and am very warm with no bulk.

The Altitude top is so comfy and fits beautiful. It looks good and well made.

I bought this top under a bit of duress from my lovely wife who had read all about io Merino & how good the products were, I really wanted something like a tank top however right from the first morning I found myself loving the top, it keeps you warm on a 1 C to @C early morning row but keeps you cool on a 18C row as well. Due to spending many years out in the sun with minimal protection I have the usual skin damage & I'm wrapped that the top seems to stop any sunburn from happening. When rowing fairly hard I'm very aware there's little to no moisture on my body except around the groin area which is mainly due to my non io Merino rowing shorts as I have the io merino boxer shorts which work a treat. I find the high neck & long sleeves really good as its protecting the neck area from the sun & cold plus when it does warm that bit, you can undo the zip allowing a more airflow. I just cant say enough good things about this remarkable product, being a 4th generation wool grower, I'm excited by the clever use of one of the greatest underutilized products around ! Be careful on sizing as this product needs to be firm on you,

Too good, love it. Fits like a glove, used it on an early morning 50km and it was spot on. Found that undoing the zip allowed me to cool down enough to be comfortable. Washes well, doesn't lose shape.

All I expected great product

I bought an Altitude Zip a couple of years back. It sat forlornly in my wardrobe, hardly used. Wasn't quite sure when best to use it. Then on one of our miserable mountain mornings this winter, strong icy gales going wild, I got the bright idea to try it out on a trail run that I was reluctant to begin. Amazing. First, it's luxuriously soft to touch. Second, it kept me remarkably warm, yet breathed beautifully as my body warmed up. And the stretchy arms make it easy to keep your hands warm as you need. I was blown away (so to speak). So much so, in fact, that after a few more outings I promptly ordered another. It's now my go-to top for winter trail running and I wouldn't have it any other way. Thank you IOMerino!

Purchased this for my partner to wear under his leathers whilst riding his motorbike. Fits him perfect. The thumb loops are great to stop the sleeves riding up the arm and the drop back hem is wonderful, it allows the top to stay tucked in whilst bending forward on the bike.

The top I bought is well made but I think not the colour I ordered. I also dislike the ioMerino name tag that is sewn onto the front bottom left corner of the top. Firstly it looks cheap. Secondly I am not proud to wear your label.

Fits well, comfortable and just right for the cold mornings on the Mountain.

Love the fit, the long body, the thumb loops, the ability to regulate temp with the zip... and of course the softness, comfortability and warmth... so good. My second altitude, my first zip... I'm sure there'll be more. And customer service is first rate too!

not made in China so thats a plus, nice & long in the body so it won't pull out, haven't worn it as yet but I get the feeling I'll be back for another. Thankyou

As the weather gets cooler, works well under a polo shirt.

I bought this one for my husband to use on a trek as I have one and absolutely love the softness and comfort of the sweater and it’s so light and easy to store in my pack too