You get a bag of 20 of the spikes; It is about One and three-fourths inch in height and thin. Each spike comes with a screw for attachment.

Screwback Spike description
height: 1 - 3/4 inch (44 mm)
base: 5/16 inch (8 mm)
color: silver
base: steel
screw type: metric- 4/.7 coarse, 1/2" length
shape: round thin tree-like spike