StudioFX 1/4" to 3/8" Convert Screw (10-pack) Adapter for Tripod 1/4" to 3/8" Convert Screw Adapter Thread Adapter with female 1/4" thread to male 3/8" thread. It works with our Double Head Stud w/ 1/4" to 3/8" thread, and make it work as a Double head stud w/ 3/8" to 3/8" thread. Material: Metal 10 pieces pack