RIYIN Mountaineering Climbing Rock 30KN / 6700lbs Zip Line/Wire Cable Trolley Pulley Heigth: 11cm / 4.3inchWidth: 8.5cm / 3.13inchLenght:2.9cm / 1.143inch Stainless steel sheaves for excellent durability. Closed Strength: 6700lbs / 30KN  Maximum allowable speed: 35 m/s The wheels have bearings, not just a metal shaft CE Certification: EN12278