The only variation between the different sizes is the height of the beam (the beam is the longest part of the iWalk that extends from the foot to the top/front portion of your leg), the optimal height the beam should be tall enough that the upper thigh strap can be secured as high as possible on your leg, and low enough that you can bend over at the waist without the beam digging into your torso. Each iWalk size has a different beam length that fits a certain range of leg lengths. It is not necessary that the iWalk beam hit at the exact same place on each patient, as long as the iWalk reaches within the correct general range on your leg, it will work perfectly!
Below is the size chart for you to choose the optimal size for your height and leg length. Please be aware that while height is a great way for the average person to choose their iWalk size, using your leg length is more exact, especially for people who have longer or shorter than average legs.
To find out your leg length, please measure the inside of your leg from the crotch all the way down to the floor (with shoes on). We suggest wearing your shoes that you will most often be wearing with the iWalk when you measure, as shoe height can increase the length of your leg.