====== Gentle Leader, The ======
AKA The Head Halter
FAQ 
  * http://www.vetsol.com/webdocs/Gentle_Leader_FAQ.cfm
Some say it is a nonsense.
  * https://www.nitrocanine.com/blog/2015/02/10/the-head-halter-torture-pain-and-nonsense-explained/
  * http://www.whitetigernaturalmedicine.com/craniosacral-therapy/gentle-leader-dog-leash-potential-health-risks
Others say it is effective.
  * https://paws4udogs.wordpress.com/2011/10/28/busting-myths-about-the-gentle-leader/