Different models of Sinar Shutter

Can anyone explain me which are the different types of Sinar Shutters?
In ebay I only find the Sinar Copal f5.6 Auto Aperture model but I know there are others. I want to use it with a Sinar P to put barrel lenses.
Which is the best model for this configuration? All have the same speeds?

Thanks!

Try this: http://www.largeformatphotography.in...=sinar+shutter

Thanks Ari!