Does anyone know about the Slik SBH-320 Ball Head? I am very interested in the 320 but, am somewhat confused. There seems to be a SLIK SBH-320 DQ which is surprisingly somewhat cheaper. The best I can tell is that they are the same ball head but, the DQ comes with a quick release. I must be missing something, though. How can the model featuring the QR be cheaper? Does anyone know if they are the same head or not? What are the differences? If one chooses the model with the quick release, where can he locate the QR plates, for other equipment?