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Ultra Zip - S.A Rogaining Edition

Fabric Guide

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The Men's Ultra Zip Base Layer top is as soft and comfortable as ever combining all the natural benefits of our finest MicroMerino® fabrics with just enough nylon to create our most durable fabric ever to withstand the most demanding adventures. Extra comfortable, extra durable and Merino-rich, perfect for adventure racing and what in Australia, we like to call ‘bush bashing’.

It is the ultimate in versatility and temperature regulation; roll the sleeves up, and pull the zip down when it’s mild and pull the sleeves down, zip up and thumb loops on when the temperature drops. Wear it on its own to stay cool in warm or mild weather, or as part of a layering system when the temperature drops.

This Base Layer is packed with extra performance features like tag-free labels and flatlock stitching helps eliminate chafe and maximize comfort. The high collar and ¾ zip add greater temperature regulation, while the thumb loops keep your hands warm and stop your sleeves riding. The reflective trims have been added for extra safety in low light.

Print to order. Exclusive for SARA printing. 

Designed with a body-skimming, sports fit.

True to size.

 Model wears size medium.

Made with lightweight 83% superfine Australian Merino Wool, 12% Nylon for durability and 5% Elastane for an easy four-way stretch and freedom of movement.

Lightweight 160gsm

83% superfine Australian Merino Wool

12% Nylon for extra durability

5% Elastane for an easy all-way stretch



Customer Reviews

Based on 19 reviews
alan davis (Adelaide, AU)
My new favourite Merino supplier

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.

Ultra Zip

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.

Frank Giovanetti (Melbourne, AU)
Ultra zip

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

Lisa (Sydney, AU)
Love it

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.

Paul Giddens (Sydney, AU)
Ultra Zip

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.

Thadiusmaximus (The Villages, US)
Ultra Zip is Ultra Versatile and Cozy

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.


Fabric Guide

While Merino is an amazing natural fibre, not all Merino fabrics are created equal. At ioMerino, we make our own fabrics, using only the best quality fibres, and to very specific specifications that make the most of the natural benefits of Merino. All of them are 'Merino rich’. No cheap blends passed off as Merino. No cheaper scratchy fibres or synthetic substitutes to save money. No unethical production. And each fabric is made for a specific purpose. So if you see something with a small amount of elastase or nylon added, you can be sure it absolutely needs to be there to enhance the natural stretch and durability. 

It took every bit of our 140 years of experience in the wool industry to perfect our fabrics, but we think you’ll agree the end result was more than worth the effort.

Ethically Made. Ethically Sourced. Perfectly Natural. 


Altitude / Zodiac

Lightweight 170gsm 96% Australian Merino Wool with 4% elastane for extra stretch and comfort. A MicroMerino® Fabric. 


Ultra / Universal

Lightweight 160gsm 83% Australian Merino Wool blended with 12% nylon blended for extra durability and 5% Elastane for stretch and comfort.



Midweight 265gsm 96% Australian Merino Wool with 4% elastane for extra stretch and comfort. A MicroMerino® Fabric. 


Summerino - Celsius 

Made from 45% ultra fine MERINO (Ultra Lightweight 150gsm), 45% natural TENCEL (made from sustainably grown wood fiber), and 10% nylon for extra durability. 


Summerino - Keystone 

Ultra Lightweight 150gsm 100% Australian Merino Wool. A MicroMerino® Fabric. 


Merino Compression

Midweight 280gsm 76% Australian Merino Wool, 15% Elastane and 9% Nylon for extra stretch and compression properties.



Ultra lightweight ribbed 155gsm 100% Australian Merino Wool. A MicroMerino®  Fabric. 



Outer Weight 280gsm Fleece 100% Australian Merino Wool. MicroMerino®  Fabric. 



Midweight 260gsm 100% Australian Merino Wool. A MicroMerino®  Fabric. 



Midweight 260gsm waffle texture 100% Australian Merino Wool. A MicroMerino®  Fabric. 


Stride / Glacier / Velocity

Midweight 255gsm French Terry 100% Australian Merino Wool. A MicroMerino®  Fabric. 


Natural Merino Wool benefits: