SPRINGS: 2.5 kg - G.18800 5 kg - G.18801 7.5 kg - G.18802 10 kg - G.18803 12.5 kg - G.18804 15 kg - G.18805 17.5 kg - G.18806 20 kg - G.18807 25 kg - G.18808 Made from cadmium steel precision wire, with double rings and dog clips at each end. Interior fitted with a stop to prevent loss of tension.