Genustech have quietly dropped UV filters for the larger sized lenses.
So if you sport that phat glass then it may be a good idea to place that extra barrier to a potential lens scratch while not adding a colour cast to your shots.
Right now they have scratch resistant 105mm and 127mm UV protector filters on their website.
105mm UV Filter Deets:
105mm UV protective filter Multi Resistance coating.
This filter is suitable for the following camera lenses with 105mm filter thread
Canon HD ENG/EFP lenses 105mm filter thread (P1)
HJ22ex7.6B IRSE A / IASE A
KJ22ex7.6B IRSE / IASE
127mm UV Filter Deets:
127mm UV protective filter Multi Resistance coating.
This filter is suitable for the following camera lenses with 127mm filter thread
Fujinon ENG/EFP lenses 127mm filter thread (P0.75)
HA22x7.3 BERM / BERD
Canon HD ENG/EFP lenses 127mm filter thread (P0.75)
HJ14ex4.3B IRSE / IASE
HJ18ex28B IRSE A / IASE A
HJ21ex7.5B IRSE A / IASE A
KJ10ex4.5B IRSE A
Please see Genustech for more information about their UV filters for larger lenses.