This Incra router bit set (600-WHITESIDE) are two-flute carbide tipped models with 1/2” shank size.
INCRA Systems use router bit geometries that are widely available so there are literally dozens of sources for compatible bits. However the quality of the router bits you use will be a big factor in the results you’ll get.
American-made Whiteside bits are as good as you’ll find earning #1 ratings in both of the past two Fine Woodworking Magazine router bit comparison tests (May/June 2007 August 1999).
Each wooden hinge requires a full-radius bullnose bit to shape the hinge barrel and a similarly-sized straight bit to cut the mating halves of the hinge. This set contains all of the bits necessary to produce wooden hinges with 3/8” 1/2” 5/8” and 3/4” barrel diameters.