Comments about Giottos Giottos MH-656 Quick Release Arca Style Clamp Camera Mounting System with MH-646 Plate:

Mounts beautifully to Giottos 1001 ball head and replaces the "stock" circular top plate, leaving a low profile, clean look. Comes with special screw and allen wrench for that purpose. Very firm and steady with no play or wobble. I also bought an extra plate, which works well. Flip-up tabs on plates (red and shown in down/flush position in photo) are handy and keep my Nikon SLR body from rotating. Mounting screw on bottom of plates has a large flat screw with integrated flip-up (C-shaped) winding tab that allows you to get a lot of torque for a tight attachment without using tools. The safety catch is useable, and it will save your gear. Only quibble is that the main tightening screw is not as smooth or as well damped as those on the head itself, which are excellent. A little grease should fix that. Overall, I was pleasantly surprised by this "value" product; it is a very good value.