The ball head is delivered without adapter ring, therefore, such a for mounting on tripods with 1/4 "screw required. The adapter ring is to get in any photo shop for a few euros and has a 3/8" male thread, suitable for Manfrotto ball head.
The ball head is really excellent for the price, the workmanship is evidence of very good quality and the design is perfect. I particularly liked the option of a mounted camera to tilt at an angle on both sides, because the ball is held only by two lateral wells. The large lever for the coarse locking the ball joint and the lower pan disc on which is seated the head. The knurled screw on the opposite side allows fine adjustments and controls the resistance of the trapped sphere.
All in all a wonderful ball head of Manfrotto, I can recommend to everyone as an important and practical accessory to existing stands. For me it is also a Nano Clamp in use.