I'm new to running longer distance runs - and decided to invest in a vest . Used the sizing guide to help me with correct size. Very happy with my vest , I always get super warm running , and wearing this vest didn't make things worse - in fact it helped loads cause I now have access to water and sweets on my runs !! I've used the jackets several times since having it and I don't notice that I'm wearing it. Very good value for money and colour is cool. Diolch !!