In Gundam, a Bit is a remote weapon that is fundamentally similar to a funnel, except that the former has it own on-board power generators, and do not require re-docking with the mother unit with for recharging, unlike the latter.
There are bits which don't have offensive functions. Psycho Gundam Mk II's reflector bits is an example, where they are used to reflect the beam fired by its torso mega-particle cannon towards the enemy, or deflect incoming enemy beams. Nu Gundam/Hi-Nu Gundam's Fin Funnels are actually bits due to having generators and they have both offensive and defensive functions.
Bits also exist outside of Universal Century timeline, but they have limited energy capacity and requires recharging. Thus, they are more similar to funnels instead.
