Wanted Chrome Extension for a Berea Sierra Refill for a click pen.

I haven't posted for a long time. I haven't been making any pens and I had to give away teaching young Tim as my back has given up on me and I can't stand at the lathe but all that is beside the point. What I am after is the extension that Berea use to extend the length of the Sierra refill. A pen that I made for my brother a couple of years ago he lost the extension as he didn't realise it was there when he pulled the refill out. I tried to contact Brett but he appears to have problems of his own. Thank you in anticipation.