The collar and leash, whatever the type, are meant to be tools of communication more so than tools of physical control…necessary only when the situation constitutes an emergency. This is why I am not a fan of “flexi” or “retractable” leashes. I am also not a fan of a lot of misconceptions about correction collars, particularly prong collars. Most people do not know the proper technique to use the leash and collar in terms of corrections and enhancing a dog’s desire to work as a pack member. If you haven’t already been trained to handle the leash as gently as possible (as opposed to locking up your arms and tightening the leash across your body and towards the dog) I highly recommend you take an appropriate class like one of the classes/lessons developed by Tanya @ Kazzi Dog Training. Go to the Contact Page to inquire about your opportunities to improve your leash handling skills.
Below is Episode 10 of That Dog Training Show with Tanya Yarbrough regarding prong collars. (Some explicit language may be in content).
If you’re interested in a quality prong collar that is designed for effectiveness (allowing you to be gentler in your leash handling) and durability through the age of your dog, I suggest Herm-Sprenger’s like the one pictured below