Quite an expensive item considering it's a piece of folding plastic, when you can get metal punches for few quid (albeit 2 hole) so I think the excessive cost is because it's 'branded', and also no-one else seems to make these for organisers, so there's no competition.
It's quite an inefficient method of punching too, as it only comfortably punches a single sheet at a time. You can do 2 or 3 sheets but then they get stuck on the punch and you have to virtually rip them off the plastic.
Also, it states you can carry the punch around, as it fits on the rings in the organiser, but I have found that the raised punch hole makers are damaging to the pages next to it, or the inside of the filofax cover, if placed at the back/front.
Only had this a few weeks but have used it almost every day, and do I wish there was an easier way to get pages into my Filofax.