[G4] Name this device

[JayB]

Having just had the discussion about monitors and adapters, it  
reminded me that I have a couple of these adapters that have never  
been used (unwrapped to photograph).

Can any of you experts tell what the heck it is ( I'm pretty sure  
it's a monitor adapter) and which machines and monitor configuration  
required it?

I put the picture up here:
http://www.jbrousseau.com/images/AppleConv.jpg


Thanks!

~Jay