Hit or miss whether it actually fixes the leak. Supposedly it goes in without the need to remove the valve core, but it can be difficult to get the sealent in.
I think part of my problem was using it with valve extenders (in spite of the fact its advertised to work with valve extenders.
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You could fall off a cliff and die.
You could get lost and die.
You could hit a tree and die.
OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.