The extended-body version of the AN6 carburettor inlet adapter with a 7/8*20 thread, at 50.9mm long against the shorter 30.8mm variant. The additional length is the whole point: it moves the AN6 flare further out from the float bowl so the hose end clears the air cleaner base, linkage, throttle brackets and the bowl itself, and it lets you get a spanner properly onto the joint during assembly and later servicing. It also eases the bend radius on the braided feed line, which matters with stiffer hose. Check your carburettor’s inlet thread before ordering, and make sure the extra reach does not push the hose into the bonnet or air cleaner.