It makes a difference of 2.5 or 5 centimeters in crank length. Mirage crank shorteners offer a solution when: - A child's bike has been bought for growth - There is a difference in leg length - A smaller radius of rotation is desired for training or a knee recovery process The crank shortener makes a difference in length of 2.5 or 5 centimeters. Installation: This set consists of blocks with left and right-hand thread. Place the correct shortener on the crank and secure it firmly with the stainless steel bolt. 3 sizes of Allen screws are included. Choose the correct size and tighten the screws until the block can no longer move. Place the pedals at the desired height in the crank shortener. If the pedal thread is longer than the thickness of the shortener, spacer rings must be used. The set contains: - 2 aluminum crank shorteners, left and right-hand thread - 2 stainless steel bolts, left and right - 4 washers - 4 Allen screws: 4x 7mm / 4x 11mm / 4x 13mm Suitable for: - Pedals with 9/16 thread (most common) - Crank arm width from 26 to 38 mm Mirage crank shorteners (cranco) aluminum. Makes a difference of 2.5 or 5 centimeters in crank length. Suitable for pedals with 9/16 thread, crank arm width from 26 to 38 mm Mirage Article number: 735461 EAN-code: 8716812604658