Pitot-static "fin"
The photo of the Kollsman probe by barit1 shows the fin. This is to compensate for the static pressure error. Error-free static ports in a Pitot-static probe are usually of the Prandtl or NPL (old UK National Physical Lab) designs where the static holes are 12 or 16 diameters downstream of the tip. This makes for a long Pitot-static. For a short
Pitot-static, like the K'man, compensation is needed. Like barit1 said, these were mounted away from the flow distortion caused by the aircraft wing to register a correct static pressure.