The Manfrotto 520BALL 75m Half Ball Leveller w/3/8 Screw for 75mm Bowl Tripods is designed to enable quick levelling of 75mm bowl tripods with the 3283 tripod. It can also be used on the Gitzo G-1424 75mm Bowl Interface Adapter to provide a reasonable and low-profile levelling base with any of the Gitzo Series 3 regular tripods (which feature an interchangeable top plate that accepts quite quick or geared center columns as well as levelling bases.