This is a La Sorrentina Steam Arm Assembly . The Steam Arm will fit on most vintage Atomic type coffee makers.
It has some improvements over the traditional Atomic type steam arms: the frothing nozzle has four holes and can be removed for cleaning. The valve has an improved seal that is easier to replace than the original atomic type seals. All seals are made of food grade silicon rather than the rubber and paper of the vintage machine.
This assembly should fit all the following vintage atomic type machines: La Sorrentina, La Cara, Bon Trading, Brevetti Robiatti Milan, Lifeware, Sears Roebuck, La Cucina and more. May not be suitable for early Sassoon, Qalital and Stella machines.