Features:1. The portable size makes it easy to carry along.2. The retractable spring could do a great job.3. This ball shape spring lock comes with delicate workmanship.4. Made of ABS, it is sturdy and durable5. A good accessory for indoor cycling bikes.Specification:Material: Steel and ABSColor: BlackScrew Diameter: M16 x 1.5Screw Length: 20mm/0.79"Shaft Length: 11mm/0.43"Total Length:65mm/2.56“Shaft Diameter: 8mm/0.31"Max Diameter: 38.5mm/1.52"Package Included:1pcs x Pull Pin Spring Knob