Nope, your right Phil, they don't fit the longer pens, and after a while the elastic gets slack and as you fold them closed the pens slide down and obstruct the hinges when you go to close them. I've got six, on a couple the plastic trays have come out despite my best endeavours to glue them back in, the elastic has stretched on all and they're not quite long enough. Having said that I've given them a real hammering but they only lasted a year and a half.