Brick, Round 2 x 2 Dome Top

This part has multiple variants with differing stud types. Versions of this part exist - in order from oldest to newest - with an open stud blocked by plastic in the shape of a 'Y' (previously known as 'blocked open stud'), a hollow stud, and an open stud blocked by plastic in the shape of a thick 'I' (previously known as 'vented stud').

This Item is a mold variant of the following Item(s):

• Part 553a Brick, Round 2 x 2 Dome Top without Bottom Axle Holder