Review on Enhance Stability and Versatility with Manfrotto 325N Video Head Adapter Bowl Interface (Black) by Chris Shepherd

It does exactly what it says in the description. It is essentially the interface between a 3/8-16 female thread on the bottom and a 100mm or 75mm ball (through an adapter ring) on the top. Well made and inexpensive. I bought it to attach the 501HDV head to the tongue on the boom. This allows me to mount it without removing the 75mm hemiball from my head, which I also use on Manfrotto racquets when I need the head there. More convenience than necessity – that saves time. As other reviews have pointed out, it doesn't allow the ball to lean, and it shouldn't. It's just a hard adapter. You'll need to make level adjustments elsewhere.