iirc, radio buttons were an early form of bookmark in that one would rotate the tuner whose position was annotated by a scale marker, and when the radio was tun

iirc, radio buttons were an early form of bookmark in that one would rotate the tuner whose position was annotated by a scale marker, and when the radio was tuned as desired, one would pull the radio button, then push it in to set that button to that tuning. I have a memory of the tactile sensation in my fingers.