One item that is pocket-sized is a 1 1/2" x 2" pad of Post-it notes, perfect for jotting down a few words or sentences. All I needed was a pocket-sized pen to go with it. I had my eye on the Pilot G-2 Mini at JetPens, but then I saw a 12-pack of Staples brand mini gel pens for only $1.99. For that price, I thought I might as well give them a try.
I was not disappointed because the Staples Gel Mini is a very decent gel pen. The size is printed on the package as 0.8mm, which is larger than what I prefer (which is 0.5mm or smaller) but on paper, the black line width doesn't look much wider than that of my 0.5mm Pilot G-2. The pens write fairly smoothly, with the darker colours seeming to be the smoothest. I did experience some skipping with the light green, light blue, and light purple, with the light purple being the worst. The line width of the light purple also seems to be wider than that of the others.
The length of the pen with the cap on is 9.5cm (3.7in), and with the cap posted on the back it is 11cm (4.3in). Without the cap, the pen is slightly over 8cm (3.1in) long. Despite the short size, the Staples Gel Mini is surprisingly comfortable to write with, although I wouldn't want to write with one for a long time. Your own experience would probably depend on the way you hold your pens and on the size of your hands.