Fotodiox sells two Rollei-to-M43 adapters: the 10RLMicro43 ($26 on Amazon USA): Pro ($40 on Amazon USA): Fotodiox says of the Pro, 'This is one of the Pro-series lens mount adapter made with precision and pristine award standard. As all Pro-series adapters, these adapters have been specially crafted to endure professional lenses. No "play" between lens and Camera.' Is Fotodiox admitting that the standard model has play? The regular has four screws; the Pro has three. Other than that, can an anyone tell me how how they differ? Each is said to have a shipping weight of 3 ounces. The regular has an "all metal design"; the Pro, "anodized aluminum construction." Does this suggest that the Pro is lighter? Most adapters are aluminum and brass. UPDATE, 2013-08-07: According to the standard adapter's home page, the standard adapter is made of brass with a stainless steel finish. I'll bet the all-aluminum Pro version weighs less--perhaps 70g vs. 90. Curiously, as of this writing, the Fotodiox website's list of Rollei adapters doesn't even include the Pro.