This is a versatile bracket that will fit on almost any light stand. It includes two removeable, reversible studs to adapt to light stands with top studs smaller than the standard 5/8 inch.
Umbrella Bracket for Pro Light Stand
Reversible male stud with 1/4-20 and 3/8" screw thread
Reversible female stud with 1/4-20 and 3/8" female thread