Review on Slime Cycling 30057: Self-Sealing Inner Tube Puncture Sealant for 🚴 Schrader Valves, Prevent and Repair Bike Tire Leaks, 700x35/43c - Black by Paul Letho

I installed two of these on my bike and rode them occasionally for four years and just over 500 miles* before the valve stem broke. I think it was more because the hole in the rim was a bit sharp. I'll never even look at them, although they let air through the valve over time. The mucus inside seems to harden and keep the valve open if you're not careful. So clean it from time to time and make sure the valves aren't leaking after filling them with air. * Your mileage may vary.