Inner diameter (approx.): 1.8-2.5 mm Length (approx.): 75mm Outside diameter (approx.): 5 mm Material: Abs Tube + colorful reflective coating film Bright reflective series product, colorful lightweight bicycle spokes. It is a very good decorative ornament and night protective equipment. No batteries, can be used for a long time, sun and rain are present. The distant direct light back to the light refraction principle according to the light, Day or night backwards have good optical radiation effects so that the vehicle can easily find the driver's existence, Reflect good warning effect. For use in bicycle spokes, emit a strong reflection under the light of the electric flashlight or the car at night. Package included: 72x bicycle reflective tubes