Hejnar Photo precision aluminum extension spacer block for Metabones Gen 2, 3, and 4 Canon EF to Sony E-mount lens adapters providing extended tripod and L-bracket clearance. 25mm micrometer adjusting macro rail featuring an ultra-precision Mitutoyo head with 0.001mm graduation increments and a 4-position quick release clamp. 8-Inch Hejnar Photo Arca-Swiss screw adjusting macro focusing rail with 0.004 inch fine control lead screw and quick-positioning button.