Cable adjuster for top of VHB and VHBZ square slide, flat top PHF and PHBH round slide carbs.
Original Moto Guzzi part number 12937200. Ambassador, V750 Special 1969-1971, Eldorado, 850GT, 850T, T3, T4, T5, V7 Sport, 750S, S3, Convert, G5, CX100, 1000SP, SP II, SP III, Strada, California II, some California III, Mille, some 1000S, Nuovo Falcone, V35, V50, V50 II, V50 III, Monza, V65C, V65SP, V65TT, Lario, Nevada carb.
6mm OD, ~19mm long, does not include lock nut number 49938800
No doubt fitting other Dellorto carb types, as it's used on numerous Ducati, Laverda, Aermacchi, Harley, Husqvarna and other brand motorcycles and scooters. Ducati part numbers 000042954 and 016027022