Fitted one a few months back....packaging says something along the lines of 'not suitable for trailers /where weight sits on a central roller' IIRC.
Mine does sit with some weight on a central roller (and is on and off trailer LOTS...hence need for protection) and i'm pleased to say is holding up fine!
Fitted mine at a friends bodyshop (car type, not fair trade soap)....really good prep and plenty of heat (both on strip before fitting and with a heat gun when fitting was a BIG help.
DHD is right, bloody expensive, but i got mine from a chandlers in Boston MA for around £70 (21ft boat)....MUCH cheaper than in UK (and cheap by US standards too). Might be worth looking at the states anyway?
One of the best additions i've made