VHST Red Race edition.  This carb is for all out race.  28mm Choke, and spigot mounting.  2 stroke version.

Here is what Dellorto has to say:

Main Technical Features
Cylindrical bore Ø 26 – 28, with air intake aligned with the choke
2 and 4 stroke engines application
‘Cut-off’ flat throttle valve (racing type)
Engine connection: male connector Ø 36 for elastic fitting
Air intake connection: Ø 49 for elastic fitting Independent starting circuit, operated by a lever, a cable or by a fork lever
Idling system with jet and mixture adjusting screw
Main circuit with mechanical mixture adjustment by a conical needle
Versions with mixture adjusting screws and throttle valve on the right or on the left
Dual float and carburetor body bottom properly shaped
Versions with horizontal and vertical float chamber air intakes

Optional:
Red painted carburetor body
Throttle position sensor