Spike is 7/8 inch tall with a base of 3/8 inch. The hex (6 sided) base gives it good grip surface. A very nice basic looking spike.

height: 7/8 inch (22 mm)
base: 3/8 inch (hex) (10 mm)
color: silver
base: steel
shape: hexagon tree-like spike
screw type: metric 4/.7, 1/4" length