Brand new, it was amazing, but quickly, the carbon particles clumped together, and it couldn't seal a minimal hole, weeping constantly, coating everything in latex. Even worse, when I reached out, they said they were aware of the problem and experiencing formulation challenges. When I asked what to do with the two bottles of the stuff I bought (to reduce shipping costs), they said there was nothing they could do for me.

Regarding being able to inject through a valve, all top sealants run into problems plugging the valve even with the core removed because that's what they are designed to do. Stans race sealant, for example no way you injecting that, which is all good by me.