In reply to Franco Cookson:
They are pretty critical on the hole size, more then about 0.5mm over and that´s it (they have a very shallow angle on the cone). When we used the 3/8" model they were just o.k in a 10mm hole. The minimum hole depth for the 10mm model is 45mm, no idea about the other sizes.
In an irregular hole they might be a bit iffy, there isn´t a lot of contact at the best of times!
The sizes available are 1/2", 3/4" and 1", there will probably be a 10mm version available in the future from another company (I´ve a prototype of these). You´ll have to guess what size the holes are as it´s a bit difficult to tell from 1,000 miles away!
An expensive way of protecting a route though, they cost $59.95, $119.95 and $248.95 plus freight, import duty and VAT respectively.