Quantity   Component name
1 × Old / broken bike tube Flat-shaped works best, approx. 4.5 cm wide, 30 cm long
1 × String 3 mm thick, 30 cm long
1 × Washer 15 mm diameter, with a 3 mm hole (so the string fits through easily)
1 × Needle A strong needle; leather needles work best
1 × Strong thread Use extra-strong thread, not regular sewing thread