I am looking for the short 150mm extension rail for the Toyo modular rail system. There are two different versions of this. I would prefer the old one (which has a fixed cap at one end and a removable cap at the other end. By turning the fixed cap you screw/unscrew the bolt that connects it to the base rail). The newer style has a special end piece that requires the end cap from a new-style base rail to use as a wrench. I have the old style base rails so I'm hoping to find a short old-style extension rail. I would be open to the new style if it is all that is available, but I would need an end cap from the newer type base rails to come with it. Thanks!