The Pentax KX was one of the three original K-mount cameras introduced by Pentax as a replacement for the Spotmatic family of screw mount cameras.
The KX model was one step up from the KM with a more sensitive light meter, a wider ISO range, and a mirror lock-up. It had a match-needle exposure readout so that the shutter speed set was indicated in the viewfinder. The aperture set on the lens was visible in the viewfinder through a small window.
This was the advanced-amateur model of the K series of Pentax bodies. The viewfinder is very informative, with a window to see the aperture, and a needle-type lightmeter plus an indication of the selected shutter speed.
Tested and fully working.
New light seals fitted