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Keystone Tee

Fabric Guide

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Everyone knows Merino is great at keeping you warm when it’s cold, but did you know our Keystone ‘Summerino' Tee is just as effective at keeping you cool and comfortable when it’s warm?

The natural breathability and thermo-regulating properties of our MicroMerino® fabrics help keep you insulated against whatever Mother Nature can throw at you. The 100% Merino T-shirt is super fine, soft, lightweight, moisture wicking, odour-resistant, delivers UV protection from the sun and is a revolution in comfort all year round.

The Keystone Tee can be worn on its own when you’re travelling or adventuring in warm to mild conditions and is perfect on its own during ‘in-between’ weather, whether you’re travelling, hiking or enjoying the outdoors. One top. Ready for many adventures.

Warm Weather




Designed to have a casual, relaxed fit.

Model wears size large.

Made from ultra-lightweight 150gsm MicroMerino® - 100% superfine Australian Merino.

Worldwide express shipping on all orders.

All orders are processed in Australian Dollars

Delivery times: 

Australian Orders 1 - 5 business days (Star Track, Toll Ipec and Express Post)

International Orders 2 - 8 business days. (DHL)

Shipping costs:

Australia and New Zealand - Free shipping on all orders greater than $100 AUD. $10 AUD for all other orders. 

USA - Free shipping on all orders greater than $200 AUD. $15 AUD for all other orders. 

Canada, Europe and UK - Free shipping on all orders greater than $250 AUD. $25 AUD for all other orders. 

Asia - Free shipping on all orders greater than $200 AUD. $20 AUD for all other orders. 

Customer Reviews

Based on 2 reviews
Base layer?

This T is more then a t, easily can be layered over or worn alone in warm weather, merino wool on your chest keeps you comfortable in the heat or cold.

Love it

This is a great T-shirt, feels like a second skin. Too bad I shrunk it the first time i washed it, else this would be my go to for sure.


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 - 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: