It so happened I was given 5 different pens over a course of a week. Each pen had a different interface twist, pull, slide, press, not one was of the traditional variety of clicking the top. The following week I had to go to the bank to sign something. The banker handed me a pen, I pulled, twisted, pushed, and could not figure it out then I realized it was of the tradituinal variety, and sheepishly clicked the top.