3/8-16 headless weight bolt system.  This is a wonderful way to weight your cues, because you can move the weight bolt more towards the middle of the cue for better balance and control.  You will receive 2 each of weight bolts listed from .25 inches to 3 inches.

You Receive the following:
2 - .25" Long = .1 oz.
2 - .50" Long = .2 oz.
2 - 1" Long = .35 oz
2 - 1.5" Long = .5 oz.
2 - 2" Long = .75 oz.
2 - 2.5" Long - .90 oz.
2 - 3" Long = 1.1 oz.