This is an IRST equipped chin (radome) pod for early F-4B's, specifically for the Tamiya kit. While not from the very start of production deliveries, F-4B's were fitted with this Infra-red Search and Track system from ca. 1962. The pod in the Tamiya kit is the late type, having a longer non-IRST forward fairing. A simple one-piece like-for-like resin replacement part.