The Audemars Piguet Royal Oak Chronograph 26239 was introduced in 2021. For this generation of Royal Oak Chronograph, Audemars Piguet replaced the caliber 2385 with the in-house caliber 4401, visible through the see-through case back. Reference 26239BC.GG.1224BC.02 has a White Gold case with frosted finish, and a Black dial. Material: White Gold Glass: Sapphire Back: Open Shape: Other Diameter: 41.00 mm Height: 12.40 mm W/R: 50.00 m Nickname: Grande Tapisserie Color: Black Indexes: Stick / Dot Hands: Stick