An
assemblage of items used for the repair of punctures. Kits tend to contain:
Sometimes manufacturers leave out the chalk even though it is vitally useful if you want to keep your
inner tube in good shape. The same could also be said for instructions, they're not always there either.
There are also emergency kits available. Basically these can come in 2 forms. The gas bottle that fills the tyre continuously, hopefully a little faster than your tyre is going down. The other involves filling the inner tube with some gunk and waiting for it to fill up any holes in the tyre. Then you just pump it back up.
See also:
HOWTO: repairing punctures on your bike