When I pulled my first set of Chen Shin's off the scoot I found three plugs in the tire. It had a slow leak when I bought it, and I assume that one/all of them were the cause. I also went to tug on one to see how secure it was, and it literally fell out. I decided to not use plugs, but rather the Hot Melt patches that go inside the tire. I still carry a Plug kit just to get to where I am going, but prefer the hot patch. These tires are too thin to really grab onto a plug.