All our springs are made from finest Korean Music Wire and are nickel coated. These 47cm springs are for use on Pilates reformers and both half and full Pilates cadillacs. Total length 47cm. Four strengths available. Product Details: Length - 47cm Strength - Strong Suitable for - All Align-Pilates reformers, Half Cadillacs and Full Cadillacs This spring can also be used with our Combo Pilates Chair II for arm strengthening and resistance workouts with the eyelets (please note handle, karabiner and clips are not included and cannot be used for pedals)