A measure of a fabric’s waterproofness. Refers to how high a column of water, measured in millimetres, a fabric can withstand before allowing water through. Higher the number, the more waterproof the fabric.

 Breathable means the fabric allows transfer of water vapour. Driven by a difference in humidity either side of the fabric, measured in g/m2 over 24hrs. Waterproof means the membrane doesn’t allow water droplets through from the outside and is measured in Hydrostatic Head (see above). This is acheived using a membrane which is a selectively permeable barrier. In fabrics, a waterproof membrane has holes big enough to allow water vapour through but small enough to not allow water droplets in and so remain waterproof yet breathable.

 Well that depends, doesn’t it! What is it for? Plodding around in heavy rain all day with a pack on or to carry just in case or to satisfy kit check? Do you value weight saving and low pack size over breathability and features? Do you want bells and whistles or stripped back performance? Does it need ot be waterproof at all or would a windproof do? The Kamleika is a soft and stretchy option with lots of freedom of movement and incredible comfort for a waterproof shell, it is full adjustable with full length zip and pockets. The Halo is a super-light option that still offers fully waterproof protection but with reduced breathability and durability, perfect for racing or when weight is key. The Kamlite uses a mixture of both fabrics to optimise performance. The Sonic range is windproof but has no membrane so i very breathable but will eventually let rain through. When choosing your Outer Layer, consider your priorities and then compare across the ranges. WE also have a useful comparison table on each product page. 

 Just like owning a top end sports car, a performance Outer Layer is only as good as how well you care for it. In the same way a sports car still needs oil changes and screen wash, you need to regularly maintain your OMM Clothing to keep it performing at its best. It is important to follow the Product Care Instructions and use the correct wash and proofer product as these can affect your clothing’s performance. Check out our Product Care Guide for more information.