The Bogen/Manfrotto 500BALL 100mm Ball Leveller is designed to facilitate quick leveling of the 3141, 3190, 3191, 3192 & 3193 tripods, and has a 3/8"-16 threaded screw.
The 500BAll can also be used with the Gitzo G-1424 100mm Bowl Interface Adapter to provide an economical and low profile levelling base with any of the Gitzo Series 4 & 5 "systematic" tripods (which feature an interchangeable top plate that accepts rapid or geared center columns as well as levelling bases).