Every color forearm crutch is fully adjustable simply moving the cuff and Hand-Grip along the curved area.
Each size has been designed to maximize ergonomics and user comfort. Each size relates to a user's height range; this way, for example, size L is intended for user's height between 1,75m(69") and 1,85m(73").
You can see the relationship between user's height and crutches size on below table.
If you are a forearm crutch "expert", you can measure the total length of your current crutch (as in right picture), and check this lenght with the corresponding crutch size length described in the table below (h):