I used those when I rolled my own ciggs, but I never tried a joint.

What it is, is there is a small, white cone on the roller. You take a smoke tube, and place the non-filtered end over top of this cone. You fill up the roller tightly, and you slide the roller forward, and the empty tube will fill up.

If you do that with cannabis, you just tear off the fiberglass filter, and there you go, a joint. You don't want to keep the cigg. filter on for cannabis as it'[s unhealthy and not needed.

You need quite a bit of weed to roll one though. Enought to fill an entire smoke tube with, packed tightly.

If you don't put enough in, the roll comes out very loose and not tight, so you need quite a bit to roll one good.

The way I see it, if your hands and mind are capable of rolling, then just practice and roll one yourself. If you really can't roll one, then invest in a good roller.

Like this one. OCB Automatic Rolling Box - Online Shop