Collar is a gene that creates a fully connected ring around the neck. Because collar does creates a connected ring around the neck, the marking must appear to touch both the back of the neck and the throat on the import.
Minimum Collar can appear anywhere within the non-dom range of the gene (your croc must have dom Collar to use the dom Collar range) and must be at least the same width as the minimum band shown on the range guide.
Collar cannot have holes and must be fully connected with no isolated 'floating' patches.
Range 1
Range 2
Non Dom Example
Dom Example