One of the most impressive and subtly beautiful grand complication wristwatches Patek Philippe has ever produced (photographic proof here), the Ref. 5016 was in production from 1993 to 2011. But for Only Watch 2015 the Geneva watchmaker has resurrected the reference as the Ref. 5016A-010, with a case in that fabulously collectible alloy steel, and thrown in a blue enamel dial with white gold appliqué Breguet numerals for good measure. Though Patek Philippe has recently resurrected some other discontinued references with its London 2015 historical collection, the Ref. 5016A is a unique version of an extraordinarily rare reference, the total production of the 5016 model estimated to be between 200 to 300 pieces.

This is the first Only Watch edition made by Patek Philippe with a steel case, previous unique pieces for the same event were in titanium. The steel case of the ref. 5016A is the same 36.8mm size as the original, with the fabulous movement inside boasting a perpetual calendar with retrograde date, tourbillon regulator and minute repeater. For those wondering what the fuss is about the low-cost case material, historical steel complicated watches from top-end brands like Patek Philippe are collectible because they are far less common than their precious metal counterparts. Many are in fact special orders or one-off pieces. Italian collectors, the pioneers of modern watch collecting in many watches, were amongst the first to latch onto steel as the ultimate case material, with the mania in the auction market in recent years, the value of steel watches have just gone potty.

The wonderful movement as seen in a regular production ref. 5016R

Only Watch 2015 will take place in November 2015, with all proceeds going towards research into Duchenne muscular dystrophy. And as past Only Watch auctions have proven, this Patek Philippe will raise the largest sum for the charity, by far.