http://www.thewatchbox.com The Jaeger-LeCoultre Master Compressor series of the early 2000s marked a complete reboot of the JLC model lineup. Bereft of true sports watches since the 1970s, the manufacture from Le Sentier came roaring back with watches like this Master Compressor GMT. Powered by a revolutionary new sports watch movement and sealed by the best water resistance system in the business, the Master Compressors redefined high horology sports watches. The centerpiece of the Master Compressor GMT is one of watchmaking's most practical complications: a second time zone. The caliber 975 manufacture movement permits tracking of two times with AM/PM indicated for the reference time. A 24-hour dial at 12 o'clock serves that function. Aesthetically, JLC artfully integrates the reference time on a centered hand that can be hidden beneath the identically-shaped local hour hand when not required. A date completes the dial's functions. The Jaeger-LeCoultre caliber 975 was designed to elevate JLC's renowned movements to "Rolex" levels durability. Its free-sprung balance with laser-welded hairspring (built by Lange!) and full balance bridge is designed to laugh at shocks, and the ceramic winding rotor bearings remove the maintenance requirements from this cruicial automatic watch component. The Cal. 975 adds unique "Spyr" gear profiles for superb going train efficiency and uni-directional winding. JLC's practical tests have led them to conclude that uni-directional systems are the most efficient available. The Compressor crown system is a joy to use. Only a half-turn is required to lock and unlock the crown. Moreover, the color-coded system helps users to avoid "accidental drowning" due to submergence of an unlocked crown. This Jaeger-LeCoultre Master Compressor GMT is available from thewatchbox.com in outstanding condition with full box and papers. It's the ideal sports watch for enthusiasts with a taste for high-end watchmaking and no desire to compromise wearability. Video and content by Tim Mosso.