Are you still trying to understand OTS vs CF requirements? Both OTS and CF start with prefabricated orthoses. If an orthosis requires more than minimal self-adjustment at the time of delivery (expertise in trimming, bending, molding, etc.) it is considered custom fitted. A certified orthotist or an individual who has equivalent specialized training can perform more than minimal modifications for a custom fitted prefabricated orthotic. Please visit our Orthotics webpage “Tips” section for more information.