Everyone has a preference and it depends on what you are used to. They are silver with a red handle. I find they don't scratch the skin like some slicker brushes do. Any good steel comb will work on pet trims. It is important to brush out all the mats and tangles before you bath the dog, as they will only get worse once they are wet.
Bathing tends to tighten up the knots.
The most important thing when trimming nails is to not get them to short. Take off a little once a week. The quick is a small blood vessel running through the nail. If you trim the nails often the quick will recede. Clipping the nail to short and hitting the quick is not life threatening to the dog but it will make it harder to do his nails the next time.