Leica Leitz Ultravid 10 x 25 BR £449
Leica's lens technology and obsessive attention to quality have made my Trinovids lifelong companions on many adventures. There are bigger, stronger, and cheaper binoculars, but these are way ahead.
The chunky rubberised exterior conceals exquisitely crisp German optics with 10 x magnification, about the limit you can handhold in this size.
Truly pocket sized, and proofed against tropical heat or arctic cold - I have used mine in both - they weigh a mere 245g, and can be carried pretty much anywhere.
Helped by Leica precision lens engineering, the low light performance - the bigger the front lens and the lower the magnification, the more light is transmitted to your eyes - is good enough for use as opera glasses.
The Trinovids are well protected against splash and accidental damage, so safe on the deck of a boat.
Magnification is excellent for the likes of Goodwood and Silverstone.
And I understand that David Hockney uses a pair in art galleries to study the higher paintings.
Leica lenses are famous for giving a warm, sharp image with detail in the shadows. I bought a small optical platform for £15 which converts them into a crisp stereo microscope, great for looking at bugs, hallmarks, small artefacts, and perhaps even bits of patients if you need to justify the stiff cost.
I bought mine 20 years ago - there's still 10 years to go on the guarantee.
They are still available, but so are the latest Ultravids, which may be slightly brighter and sharper.
Dr Stefan Cembrowicz is a GP in Bristol