Gitzo Systematic Leveling Base The leveling base is an accessory dedicated to Gitzo Systematic Tripods, & allows quick, accurate leveling when setting up a shot. It is especially useful when shooting with a flat-base video head or in landscape photography. A head can be attached onto the 3/8'' screw of the leveling base, & the lever on the side tightens the screw securely against the head. GSLVLS fits into any Gitzo Systematic tripod via the optional 75mm video adapter GS3321V75 (for Series 3&4 tripods) or GS5321V75 (for Series 5 tripods).