The Royal Oak 25831 was the first Royal Oak to feature a tourbillon escapement. It was introduced in 1997 to celebrate the 25th anniversary of the Royal Oak. Reference 25831OR.O.1110OR.01 has a pink gold case and a silver / off-white dial.
Self-winding movement with tourbillon escapement and power reserve indicator. Hammer-winding system; crown fitted on the back. Titanium tourbillon case.