The WPA (World Pool-Billiard Association) sets specific regulations for the length, weight, diameter and composition of regulation pool billiard cues.
The length of the cue stick must be at least 40 inches long, but there is no maximum length.
The weight of the cue stick must be less than 25 ounces. There is no minimum weight.
Diameter of Tip Regulations
The diameter of the cue tip must be less than 14 millimeters. There is no minimum tip diameter.
Cue Tip Regulations
The cue tip must be made of a processed leather or similar material that will not damage the ball when it is hit.
The ferrule (the small, usually white section between the main shaft and the cue tip) must be less than 1 inch long if it is made of metal.