Yellow = diameter 35 mm, resilience 2.5 kg
Red = diameter 38 mm, resilience 4.5 kg
Green = diameter 44 mm, resilience 7.0 kg
Blue = diameter 51 mm, resistance 11 kg
All bars are 30cm long and look very robust. According leaflet containing latex rods and they give off (unfortunately) also a noticeable scent, which in my opinion is not as dramatic but that I did not use the bar wöllte. Otherwise, I am happy with the product and would recommend it.