There are really heavy but they do work. My buddie and I finished that ride and while having a beer we noticed that he had a streak of slime up his backpack and the back of his helmet. The rear wheel spun a couple of times before sealing and he didn't even notice. Shitty stuff to clean up.

 yuck. that gloop is discusting, whenever we have a punctured one come to the shop we make them go away and clean it first.

 an i think most tube and tire makers say not to use it..it will vold warranty on tires