Despite some images of the sai as a sharp weapon, it is actually blunt with prong-like extrusions designed to help catch and disarm opponent's weapons. The sai can also be thrown. A monk using a sai can strike with her unarmed base attack, including her more favorable number of attacks per round, along with other applicable attack modifiers. A sai user who attempts to disarm her opponent gains a +4 bonus to the opposed attack roll required. (You don't gain any bonus if someone tries to disarm your sai.)