F/B-flat full double
†Most modern full-double French horns follow one of two layouts defined by the position in relation to the standard three valves of the thumb-operated fourth valve. The 'Krüspe' layout places it close to the thumb lever and first valve; the 'Geyer' layout places it after the third valve. The Geyer layout results in fewer bends in the tubing ('open' wrap) which combined with a smaller bell gives a generally brighter tone; to compensate many Geyer models are made in yellow or red brass to darken their sound. The tighter 'closed' wrap of the Krüspe layout plus a larger bell results in a characteristically dark tone, so many instruments are made from nickel-silver to add brilliance.