What's stuck in my Brake Rotor

[Daves86]

Was looking at my rear brakes and saw this

Do the rotors have a counter weight, and are they supposed to move?
Thanks.

 

[Daves86]

Should the counter weight move?

 

[Ajax MD]

Looks like debris to me. Have you grabbed it with needle nose pliers and attempted to remove it?

 

[Bulldogger]

Can't say I've ever noticed something like that in mine, so I'd say it's not planned.
BDGR

 

[MrMikey4026]

Balance weight that has come loose?

 

[DREDnot]

Ive seen differing spring steel clips and pins inserted in rotor slots like that. I have heard that certain styles are to balance out some annoying vibration in that rotational mass. Ive heard that other styles are to attenuate squealing/harmonic vibrations