There's another version I found that has the cables one on top of the other, rather than side by side. It has an internal "seesaw" that applies equal pressure to BOTH cables, so you don't face plant because the front one grabbed too much. $10 plus ship.
Do you mean something like this? I have used this for a long time and I love it. You can actually adjust the amount of bias by preloading the front or rear more depending on if you like more front or more rear brake. It also allows independence so if one cable fails you are not without brakes completely.
To answer the original question- yes, you have to remove the cable from the sheath, thread it through the hole in the lever, then feed it back through the sheath. Works best on new cables.
Do you mean something like this? I have used this for a long time and I love it. You can actually adjust the amount of bias by preloading the front or rear more depending on if you like more front or more rear brake. It also allows independence so if one cable fails you are not without brakes completely.