Auray 5/8" Male to 3/8" & 1/4"-20 Female Combo AD-COMBO-S B&H
Husky 3/8 in. Female to 1/4 in. Male Drive Adapter HADPTR3814 - The Home Depot
Amazon.com: Niewalda 1/4 Inch Male to 3/8 Inch Female Tripod Screw Adapter 3 /8 to 1/4 Tripod Adapter Mount Screws, Accessories for Camera/Tripod/Monopod/Light Stand : Electronics