Description V Brake Extension Seat Bike Foldable Round Group Conversion 406 to 451. High quality aluminum alloy materials, durable for lasting use. Design for turning 406 wheel group into 451 wheel groups. Lightweight, easy to carry and use. Suitable for all big lines, popular, bird car, Eurasian code steel frame. Specification Material Aluminum Alloy Size Approx.49.2x16x5mm/1.94x0.63x0.2inch Package Includes 2 Pieces V Brake Extension Seats 2 Pieces Screws 2 Pieces Nuts Note Color might be slightly different due to the color calibration of each individual monitor. Please allow slightly measuring deviation due to manual measurement.