Variable load control knob gives full range of adjustments. Flip-lever controls suction; sets and releases easily. Grips any smooth, non-porous surface.
Big Book Catalog, Issue:65, Page:439
SPECS: 4¼" (10.7cm) x 5" (12.7cm) at bottom; 3½" (8.9cm) to top of ball. 6¼" (15.8cm) high overall.