This is an RCA dynamic/moving coil microphone with an omni-directional polar response that was manufactured circa 1965. In this image, it is the microphone on the far left.
This is an RCA ribbon/velocity microphone with a bi-directional polar response that was manufactured circa 1955.In the image with multiple microphones, it is the mic second from the left.
This is an RCA ribbon/velocity microphone with an omni-directional polar response manufactured circa 1951.In image with multiple microphones, mic is in the middle.
This is an RCA ribbon/velocity microphone with an omni-directional polar response manufactured circa 1957.In image with multiple microphones, mic is second from right.