This is one of Conway Stewart's more unusual pens. It appears to be a conventional lever filling pen, until the cap is removed revealing a rather non-standard nib. Made in England it is finished in marbled green. The barrel has a clear imprint reading "CONWAY INK PENCIL   Conway Stewart London   No. 109".  A second imprint around the barrel reads: "PAT.NO. 304922   MADE IN ENGLAND". The matching cap has no cap band, and has a black domed top. The clip features the intertwined "CS" and ends with the characteristic diamond shape. (Other versions, possibly made in Australia feature the ball ended clip).

The unusual 'nib' is a narrow tube held by a black section. The tube is slightly angled to facilitate writing whilst holding the pen at a conventional angle, which the photo above shows. The delivery system results in making a serious mark on the paper - in conventional terms with would be called a broad nib.  The ink sac has been replaced.