Need a quick, easy guide to working out which layer and size is best for you, where you’re going and what you’re doing? Look no further.

Unlike some companies, we don’t bombard you with 5,000 different styles to choose from, we like to keep our range simple, with different options for different things. Keep in mind, none of this is gospel – if you want to wear an Ultra top snowboarding, go your hardest. All our layers can be worn for everything. This is a guide on what they were designed for, and what we consider them best for.


The Altitude Range

This ‘base layer’ range was originally designed for snow sports and on-mountain sports, however it has quickly become a jack-of-all-trades, go-to thermal base layer. The Altitude Range is the perfect lightweight thermal layer for core warmth when you’re layering up, yet versatile enough to be worn on its own in milder conditions.

This range is longer in the body and features a drop back hem designed to tuck into your outer layers, or sit over bottom layer so you don’t have exposed cold spots when you’re on the go. Ideal bike riding where you’re bending over and you don’t want your top to riding up or a cold patch at back. Also a favourite for tall people.

The Altitude Range is ‘contact fit’ to maximum thermal properties and sit flat under other layers. Made with 96% superfine Australian Merino and 4% Elastane to give extra stretch.  Designed to be body hugging and tight all over.

Perfect for snow sports, cycling and running. 

The Ultra Range

Our newest range was developed with Ultra Runners in mind. Extra comfort. Extra durability.

The sporty fit is still streamlined and ‘body slimming’, but not ‘contact fit’ like the Altitude range. For those of us who love the Altitude Range but may want something a little less clingy, this one’s for you. The Ultra Range is regular fit (so no added body length) and a true to size – so if you’re usually a medium, you’ll be a medium in this. No need to size up or down. Made from our first ever Merino blend fabric with 12% Nylon. The fabric combines all the natural benefits of our finest MicroMerino® fabrics with just enough nylon to create our most durable fabric yet. It's as soft and comfortable as ever, and still Merino-rich but tough enough to withstand the most demanding adventures.

Wear it on its own to stay cool in warm or mild weather, or as part of a layering system when the temperature drops.

Perfect for running, adventure racing and hiking.

The Universal and Celsius Ranges

This one’s easy: all the amazing properties of our MicroMerino® fabrics, but in an easy, casual fit.

So if you want a little extra room to move, this one’s for you. Still true to size, so if you’re usually a medium you’ll be a medium in this. The Altitude is tight, the Ultra is sporty, the Universal and Celsius ranges are regular fit.

The easy fit of these collections means it will sit nicely over another layers, but they are super soft to wear on its own as well. Works for any activity, from high-intensity stuff like running and riding, right through to camping, hiking and beyond. Particularly good for travel – whether that’s a long flight or a road trip. 

The Universal Range is the exact same cut as the Celsius but made with the same fabric as the Ultra. Casual Celsius fit. Ultra fabric. Make sense? So packed with the high performance of our Ultra range, just in a comfortable, easy cut. Perfect for travelling, exploring, hiking, running, riding… or just wearing every day.  

The Celsius Range we refer to as our Summerino range because the ultra-lightweight, 100% Merino fabric make it the perfect choice for warmer weather.

Remember, we’re so confident you’ll love what you end up with, we’ll give you your money back if you don’t love it as much as we say you will. And as always, if you need any help choosing the best layer for you, feel free to contact us any time!


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: