Are you looking for a LNB or a LNBF? (LNBF has an attached Feedhorn and an LNB bolts to a feedhorn). C-band or KU-band? C-band LNBs and LNBFs are not usually dual band (high/low) and are typically standard single band with a single LO frequency and no switching.
A hobbyist favorite and proven performer C-band LNBF is the GEOSATpro C2.
If you are looking for a LNB, I will let someone better informed assist.
Should get a Cband - Ku Combo the has both lnb on one unit that way you can have the best of both worlds. on KU I would go universal khz 10600. you can buy here I believe from WSI or you can but DMS but you should review any products before buying so you can purchase one that you will like.