I'm talking about the Uni Ball Style Fit and the Pilot Coleto.
These pens are like those 4-in-1 pens where you push down to select a colour, but the special thing about these pens is you can choose the colours you want. They sell the empty pen bodies and refills separately. Uni has a 3 and 5 refill body, and I think Pilot has a 4 refill body. Uni also has a single refill body, which looks a lot like a refill since the refills also come in tubes of similar width. The refills cost $1.70 and the single refill body costs $1.90. Uni also has pencil refills.
These are actually quite expensive, a fully loaded pen may cost >$10. I think the refills look quite thin so they won't last very long either. I mean, even normal gel ink refills, which are much thicker than ballpoint refills, don't last a long as ballpoints.
Uni refills seem to be the same as the Signo DX (they come in 0.38 and 0.28) or Jetstream. It'll be nice to be able to carry up to 5 colours of Signo at the same time. (The Signo DX is my favourite pen) It'll also be nice not to have to worry about capping the pen. (In my experience with refilling the Signo DX bodies, the cap is the first part to wear out, so when using the pen I only cap it when I'm done for the session)