Weird brake sound

So lately I have been hearing this sound every time I step on the brakes. Just image a player card tape to a bicycle wheel and when u pedal it makes that sound. Just not as loud but definitely audible specially if I'm driving next to something that can refect the sound back. The sound goes away when the truck reaches 20mph or less. The brakes feel fine when I step on it though. No vibration or anything. Ideas?

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