The modules are "potted;" that is, the circuit board and components are put into the aluminum case which is filled with liquid plastic, known (not surprisingly) as "potting compound." The module is mostly a big transistor that handles the coil switching that was in prior years handled by the opening and closing of the ignition points. If something goes wrong, the module overheats and could melt the plastic block.
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination ATs, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
ECO Green: '15 FCA Jeep Cherokee KL Trailhawk