The 16710 is the GMT-Master II most of the world has actually handled: roughly eighteen years in production from the late 1980s to 2007, the last of the five-digit references, and the most versatile GMT ever offered - Pepsi, Coke, or all-black aluminum bezels on Oyster or Jubilee bracelets, six looks from one watch. It is also the Coke bezel's final appearance to date; the ceramic era that followed has never reproduced the scheme. Sources split the start between 1988, launched alongside the 16700, and 1989, when watches reached the market in number.
Its long run means eras within the reference: tritium dials to Luminova to Super-Luminova, hollow to solid end links around 2000, drilled lugs to no-holes cases, and at the very end a handful of caliber 3186 examples and the error 'stick dials' whose Roman-numeral II lost its serifs. None of this is trivia; on a reference produced this long, these details are the dating instrument, exactly as dial eras are on the 1675.
The value entry to GMT collecting and the last GMT that feels vintage while wearing modern. Configuration drives desirability - Coke and full-set examples lead - and late-production quirks carry premiums that demand documentation.
Production windows and specifications compiled from documented collector references and period catalogs, cross-checked across independent sources; manufacturer records for this era are approximate by Seiko's own account.