The Rolex Explorer II Ref. 16570 was produced from 1989 to 2011, and this 2006 F-serial example sits in what collectors have increasingly come to regard as the most desirable production window of the entire reference run. The F-serial 16570 carries the Caliber Caliber. 3185 — the movement that powered the reference through its earlier and middle production years before giving way to the Caliber. 3186 from 2007 onwards — and it arrives at a moment in the reference's life when the case and bracelet construction had reached its most refined expression. The solid end links and no holes case of this period represent a meaningful upgrade over the hollow links of the earlier 16570 production, giving the bracelet a weight and presence that later references replaced with improved movement architecture but not superior metalwork.