1. ABS material, strong and durable, resistant to pressure and fall
2. Rounded edge design, durable, anti-collision and anti-drop
3. Square design, light and portable
4. High-density EVA foam shaft, thick and hard, moderate hardness without hurting the wire
5. Material: ABS
6. Dimensions: about 8.2 x 7.4 x 3cm for 2 axle, 13.6 x 7.4 x 2.7cm for 4 axle, 19.9 x 7.4 x 2.7cm for 6 axle, 5.8 x 1.17cm for foam axle