Hand_radio is a pickable item featured only in S.T.A.L.K.E.R.: Shadow of Chernobyl.
The item can be found in the Dark Valley area, north of the X18 entrance building, in the same place where the player finds guitar. There are two versions; one which looks like the player's head-mounted flashlight, but it's a radio. The other resembles a typical "walkie talkie". The latter is located elsewhere. It appears that, at one point, they were going to be items in the game, but most likely the idea was dumped. You can't use it, nor can you sell it. Both items are seen to be used by NPCs (Stalker's flashlights, and important NPC's using radios), and may not have been intended for the player's use.