I too have an Air Boss (currently my only bag on Safari in South Africa and Mozambique). I concur with the opinions here about the ‘claw’ strap as supplied. Unbearable! However Red Oxx supplies me with their ‘Long Hauler’ version of the OpTech/ Tom Bihn strap. It is transformational, but there is no getting around the fact that, no matter how good the strap, 15kg on your shoulder is not easy