preliminary
Technics' original honeycomb loudspeaker.
More educated looking than the later SB-M series, with a leaf tweeter made of polyimide film and a 32cm woofer with pure-aluminium cap, reversed roll urethane edges and diecast aluminum edges.
Two protector reset buttons, one for each driver, as on most Technics 'speakers from the time : SB-F3, SB-X50 etc.
The export SB-10 and the japanese original seem to have completely different crossovers frequencies and SPL.
According to listeners, the SB-10 is a much better loudspeaker than the later honeycomb incarnations...
Given the timeframe, 1979 vs. 1981/82, this wouldn't surprise me.