I made a couple that I gave out to some of my students and my instructor. Stainless steel, rounded point on one end, pretty thin (made from UMD spindles, about half the size of a CD spindle).
I know my instructor has used it while escorting subjects at the jail to good effect with pain compliance and some joint locks. He attached a key ring and slips the kubaton into his duty belt for easy access.
I know one student used his as a fist load to good effect.