It is a ¼” X 2” X 36” anodized aluminum bar, with a V-angle of 145 degrees, and a precision milled ball release notch 30” from one end. The end resting on the green is milled on the underside to reduce bounce when the ball contacts the green.

When checking the speed of a green, select a level area of about a ten foot circle. Place a golf ball (small, dimpled), in the notch and raise one end slowly (20 degrees) until the ball rolls down the V incline and out onto the green. Do this with three balls from the same spot and record the distance from the coin or tee to where the ball stops. Repeat with three balls from the opposite direction.
Add the 6 distances and divide by 6; this will give the average greens speed in feet. For example: if the total adds to 54 / 6 = 9, the speed of the green is 9.

General information on green speeds

REGULAR PLAY        : TOURNAMENT PLAY
8-9 feet fast             : 10-11 feet fast
7-8 feet semi-fast    : 9-10 feet semi-fast
6-7 feet medium      : 8-9 feet medium
5-6 feet semi-slow   : 7-8 feet semi-slow
4-5 feet slow            : 6-7 feet slow