The Teac AL-700 is the rarest of all ELCASET actually produced.
Like the Technics RS-7500, it was rushed into the market after lengthy engineering on far more high-end (and beautiful) pre-production samples... only to disappear just as rapidly.
Dolby-equipped, it could however receive a dedicated external RX-10 dbx processor... not photographed (but the i/o loop is at the back of the production AL-700s), and a wired remote... not photographed either
Both items were however shown, functional, during a couple of japanese hi-fi shows.
Alongwith its 3-head & Closed Loop Dual Capstan, soft-touch transport keys and hefty 18 kilos the AL-700 already sported a "rec mute" function to help search&program functions - this s&p feature is however lacking.
Some contradictory info I have mentions that it could be implemented with the help of an additional external box but I have yet to find an image of it.
As can be seen here, the drive is not a Sony EL-7 or Technics rebadge - and it is fully diecast aluminium, unlike the four Sony or the Technics.
There were two runs made : one with a silkscreened model number (as shown here ; s/ns start with a #2) and one with an eeenormous 3-part badge splattered on the same spot, the lower tier of it bearing an "ESOTERIC SERIES" tag (s/ns start with a #3), additional scripting atop the door and two big bolts added there too.
Both runs were exported but the former version is by far more common (if the AL-700 ever was "common") ; Japan only saw said former version.
Given the dismal amount of AL-700 Teac allowed itself to sell or more probably discount between 1978 and 1979 (see the USA ad below right), this adventure must have cost quite a few ¥. Apparently about 10,000 units were made - where did they all vanish ?
You can see a (the ?) japanese AL-700 here and nudies of same here.