Theres one type i will only ever use... its got 3 prongs and it tightens as you undo just shove a half inch ratchet in the end! worked unbelievable on mine.
http://cgi.ebay.co.uk/Draper-Expert...t=UK_Hand_Tools_Equipment&hash=item2310e50a50
@dac69er: i agree but at times, if your engine has gathered quite some miles since the last service or has been sitting for a while, they can need a nudge from a filter removal tool to get it off..
i use the free hammer and flathead screwdriver sometimes if i forget the tool