is that the WCL and TCL attached together? if so, more info, please! the other week while walking around, I had imaged it would be cool if there was some sort of threaded barrel that would allow both the WCL and TCL to attach to at the same time. I've seen some in the past, but for bayonet-type mounts (pretty much like two rear caps stuck together). I can't find anything threaded for 49mm.
edit: I just found something I could use -- a 49mm male-to-male coupler! well, assuming the rear thread pitch is the same as for the lens filter threads.