Part No. Description Base Ø(mm) Post Ø Height(mm) Mount PlateL x W (mm) (in) (mm) 293786 Slide/Swivel Top 228 2-7/8" 72.6 160 340 x 195 Friction clamping top.Moulded nylon cup insert provides smooth swivel performance.Low profile base with 6 x 8mm countersunk mounting holes for a solid support.Aluminium casting made of noncorrosive material.Powder coated aluminium swivel.Anodised base.360o rotation.