This is really cool!   It is a chaff dispenser for a B-52 Bomber.  Below is a description of how it functions.  Might work to block your mother-in-law's cell phone (maybe not).  It has a light dimmer that works like an iris on a camera.   These are used but the face of the instrument cleans up very nicely.  Some paint lose on outer shell.  

 Would make a great gift for your aviator! 

Chaff - Radar Countermeasures

Chaff and flares are defensive mechanisms employed from military aircraft to avoid detection and/or attack by adversary air defense systems. Chaff consists of small fibers that reflect radar signals and when dispensed in large quantities from aircraft, form a cloud that temporarily hides the aircraft from radar detection. The two major types of military chaff in use are aluminium foil and aluminium-coated glass fibers. The aluminium foil-type is no longer manufactured, although it may still be in use.