Part One: By initially sending you three different sizes to try based on your average shoe size. After the USPS Priority mail package arrives give Ed a call at your convenience and he will spend about 15 minutes going over the simple and easy but important sizing process. Your shoe size only gets us close to your properly fitted size. It's your arch length, foot width, arch height and personal preference that determines your correct size. After about 15 minutes or as much time that is required, we will be about 90% sure of your proper size after our first telephone fitting. We will immediately determine which sizes are too large or too small. It is especially important not to oversize a true alzner type design arch support orthotic. Over-sizing is the first thing we eliminate. Just like when we try on new shoe in the store, we need to walk around some before we are confident that of the size and width. Sometime we are stuck between two different sizes and you need more time to figure out which one is best over the long run. Not a problem. Take the next few day or even a week or so to alternate between the different sizes so you (we) are confident they the correct and proper fit. Got any question while wearing your new My Healthy Foot arch supports? just give us a call. We pick up the phone seven days a week! Part Two: After we together determine you correct and proper size keep the one pair that is you correct size along with the Cut-to Fit shoe cushion insert and return the other two pairs via USPS Priority Mail (just under $7 shipping cost) to My Healthy Foot. Use the return mailing address found on the Part One Priority Mail package we sent to you. After we receive the two pairs that where too large or too small, we will send out two more pairs in your correct size along with two more Cut-to-Fit shoe cushion inserts. It is simple as that! Let the postal service do all the driving around for you. Give us a call if you have any questions (714) 785-6986.