HB,
Kinda neither. You get a copper plate which has an arrow shaped pin on it, which is poked into the copper wire and wrapped around the end of the lead, to make a bit of a loop, then the lead, with the copper loop bit protruding is basically shoved up the end of the cap until it marries up with where the spark plug enters. Hope I'm making sense.
Worth every cent of the $5.00 just to learn the build technique. Once in place they seem to stick there good.
Bit more work than the bulky no name black rubber ones but, betta.
all the best
Pete