Oris Big Crown ProPilot Altimeter Watch Review

Oris has launched the Big Crown ProPilot Altimeter - the world's first automatic mechanical watch with a mechanical altimeter.

Described as the most innovative pilot's watch in Oris history, the timepiece is designed for "ambitious explorers": pilots, mountaineers, explorers, research scientists and others that work at altitude.

The Oris Big Crown ProPilot Altimeter has a 47 mm multi-piece stainless case which houses an Oris automatic movement, and a Swiss mechanical barometric altimeter and barometer movement.

The altimeter is operated using a screw-down crown at 4 o'clock. When screwed down into 'Position 0', the altimeter is inactive and the watch is water resistant to 10 bar. To activate the altimeter, the crown must be unscrewed to 'Position 1', indicated by a red ring. The altimeter can be calibrated when the crown is pulled out into 'Position 2'.

The current altitude is displayed via a yellow indicator on the dial, while the corresponding air pressure is displayed by a red indicator. The altitude scale is shown on the outer dial ring, measuring altitude up to 15,000 feet or 4,500 metres. Two models have produced, one with a scale in feet and the other in metres. The air pressure scale is positioned between the altimeter scale and the central dial.

To ensure the altimeter mechanism was small enough to fit inside a wristwatch, the altimeter hand had to be extremely lightweight but also stiff enough to avoid tolerances and inaccurate readings. The hand is therefore made from a laminated carbon fibre, making it seven times lighter and 10 times stiffer than the average watch hand.

The inner workings of the watch are protected from moisture when the altimeter is activated using Oris' patented new altimeter adjustment and venting crown, which uses a membrane made of PTFE to create a vapour barrier.

The Big Crown ProPilot Altimeter comes with a choice of textile strap, leather strap or metal bracelet.