Pipercross is another filter, like a K&N.
I prefer the Pipercross as it uses a dual-layer of differing densities of foam, to give better filtration of particles. Like the K&N is can be "washed" and re-oiled (you get a can of oil) so it will last a lot longer than the OEM paper filter.
f you want to practise your English, try reading Shazaam's article:
http://ducatisportingclub.com/xmb/vi...=1701#pid12578 I doubt there is much between the K&N, Pipercross and the DP one to be honest, but you can get a Pipercross filter for around £40 - I think it's cheaper than the K&N ?
I still use the K&N oil filter cartridges. As Frank says, these come with a pre-drilled nut on the end making lock-wiring them really easy.