Most ink pens these days have built-in plastic shirt pocket clips located near the top of the pen. But I remember a popular disposable pen back in the day (probably a Bic) that had a metal clip that could be slid up and down the length of the pen or taken off completely. Would love to get my hands on one to see if it fits my 510 as a safer means of carrying it around in my shirt pocket or on my t-shirt's collar. Anyone seen any of those types of pens lately?