This keyboard was featured in my Differences between and classifications of 122-key Model Ms comparison topic.
The Type III 122-key Model M Function Key Keyboard was a major overhaul over the previous two types' design. The design language of Type III is much closer to that of other Model Ms than Type I and Type II, which were both made to resemble the 122-key Model Fs they replaced. Type III is also smaller and lighter than its predecessors and completely did away with DIP switches. Whilst the protocol remained the same, the cable's plug was swapped from 240-degree pin arranged DIN to modular 8P5C (ethernet-like) to suit its typical host machines - the IBM InfoWindow and InfoWindow II series display stations. Whilst still possessing a coil, the cable's shape is also a flat design rather than round and it can be routed straight out the middle of the keyboard's rear or through two channels going to either side of the said rear. Unlike Types I and II and the "F122", Type III's 24-key function key block was only labelled with an "Fxx" nomenclature.