In my small portfolio, the Sinn 900 Flieger («pilot») is the oldest and one of the first «proper» watches I ever bought. And for me, the 900F is still one of the hottest watches in the Sinn range.

The 900F has a very clean and uncluttered face, while still offering a lot of information: a typical 7750 with time, date and chronograph, a second time zone indicated by a further hand from the centre and a rotating pilot’s bezel for measuring a further time (or setting a third time zone).

So how did they get so much information on the dial without it becoming a complete mess? Time, date and chrono are a very plain white on a pitch black dial, the (applied) indexes are chamfered according to the quite large sub dials, which are slightly lower than the rest of the dial. The indexes for the third sub dial, the second hand at 9, is printed in a dark grey and therefore nearly disappearing, while the hand and the numerals for the second time zone are kept in silver. These three shades of grey (and no real colour) result in a very pure, functional, yet appealing «porsche-designesk» watch face. As the indexes and the main hands are fully lumed, the night view is even more impressive.

The pilot’s bezel is located under the slightly domed sapphire glass on the rehaut and is operated by a crown at 10. This allows the bezel of the case to be kept very narrow, contributing to the quite elegant look. The case is manufactured by Sinn’s daughter company SUG in Glashütte (you can see the SUG logo between the lugs if you remove the strap) and is hardened (Sinn calls this tegimented) to >1,000 Vickers, so that it looks like new even after years.

Even the pushers look very straight-forward, simple and stylish, but with what Sinn calls D3-technology, they contribute to the water resistance of the watch of 20 bar. I believe – but never was brave enough to test it – you can operate them even under water. Other Sinn watches with «D3» offer that feature «officially».

The case also withstands magnetic fields of up to 100mT (=1000 (or mil) Gauß) and features the Sinn «Ar-technology», which consists of a nitrogen-filled case, a drying capsule filled with copper sulphate and high-end gasket to prevent ageing of the oils of the movement.

A diameter of 44mm and height of 15.5mm does not really qualify the 900F as a dress watch, but its clever design makes this tool watch perfectly acceptable to fit even with a suit and tie outfit.

In my portfolio, this is maybe the most versatile and most «useful» watch. This watch just does the lot; I even took mine with me for diving (as I unfortunately sold my very first proper watch, a Sinn diver …)