High Quality Aluminum Alloy: ROCK BROS bike cargo rack is made of high strength aluminum alloy material with stainless steel screws, helps you ride freely in rainy days or bad weather. The rear bike rack has strong load-bearing of MOST 165lb capacity, suitable for daily use and long distance cycling. Universal Cargo Rack: Mainly suitable for most mountain bikes, fits ROUND seat tube diameter under 3.2cm(1.26ines). NOTE:DOES NOT fit soft-tailed bike, carbon fiber bike, foldable bike, small wheel bicycle, rear suspension bike, etc. Easy To Install: Adjustable quick release bike rear rack clamp for installation and remove simply, with tools, installation instructions and video, you can install the bike luggage cargo rack easily. Firm&Durable: Three-point fixation is more stable, adjustable support rod for easy length adjustment, allows you adjust the rod length to fit your mountain bike frame, perfect as a bike luggage rack and for carrying equipment on your travel and commuting. Side Protection: Two “W” shape side bars protect your luggage from scratching by the wheel or spokes. With elastic cords and red rear reflective lamp, the bike back rack provides extra security while riding.