The latest variation on the Hamilton Khaki Aviation is the Converter Chronograph, a blue dial slide rule bezel watch, which makes a budget alternative to the Breitling Navitimer.

Your scales are set on the bezel and the inner chapter ring too, so rotating the bezel lets you calculate speed over a given distance, or pounds of fuel being burned by the minute, assuming your biplane has sprung a leak at the Reno air races. All handy stuff. The chrono functions and day/date features also make this a versatile all-rounder.

At just under £2000, this isn’t your entry level Hamilton, it has a genuine skillset worth talking about. Strong competition at this price point from Sinn, Oris, Victorinox, or maybe the Citizen Promaster Skyhawk would do the job at £1400 or so?

More at the Hamilton site here.