Dunno if this has been posted before, but I just wanted to share and have others post their favorite combo, too! I love the look, weight, and feel of my Cartier Santos pen & I can't seem to write comfortably with the itty bitty skinny agenda pens.... For awhile I just carried the pen in patch pocket of my purse, but that's so humbug. I was determined to use my fave pen with my fave agenda. I bought the filofax inserts, so this is what I've wound up doing. I slide the clip part of the pen onto the "pocket envelope" and it's holding up very nicely! It looks great from the outside, and it stays put. I thought about trying to slide the clip onto the pen loop, but my pen is too long & sticks out one side if I try that. If you were using a shorter pen, that would work too. Come share your pictures of your fave pen with your agenda!