The Explorer II was built for a narrower job than its name suggests: cave explorers and anyone else working without daylight, who needed to know whether the hour hand meant morning or night. The fixed 24-hour bezel and the large orange arrow hand answered that, and on the 1655 the arrow was not independently settable, so the watch is a day-night indicator rather than a travel watch. The caliber 1575 drove it, the case measured 39 mm, and the bezel carried hash marks between numerals rather than the arrow markers that came later.
It sold poorly for most of its thirteen years and was the least loved Rolex sports reference of its era, which is precisely why it is now among the most collected. The Steve McQueen nickname attached to it decades later and appears to have no basis at all: the watch McQueen actually wore in photographs is a Submariner. The file records the nickname because the market uses it, and records that the attribution is unsupported.
A commercial failure that became a collector reference, with a nickname the evidence does not support. Dial and hand originality decide the price; the orange hand is the part that gets replaced.
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.