I have been using the progressive suspension style plug for the last 15 years or so. http://www.progressivesuspension.com...pair-kits.html
Every one that I have used have outlasted the tire. Never had one fail or any problems with cords cutting them. I have never really heard anyone recommend the string type before. What are the advantages of the string type over the progressive style? I'm guessing they are a lot cheaper, what else?