DAF was first introduced by the device known as the: SPEECH EASY! I had one back in around ’01. It wasn’t cheap by any means, wanna say it was about $5k. But DAF does it layman’s terms “trick the brain to slow down speech patterns while also initiating diaphragmatic breathing behaviors”—If your stutter is so severe, speak (or have a relative do so for you) to local OVR (Office of Vocational Rehabilitation) this will eat up most of the cost for a device. I think my folks only paid $500 for mine. But I was well aware of the official price!!!