Tandy sells edge coat in black and brown maybe some others, i just use the two. its thicker so wont run or bleed and it covers any uneven dye problems on the edges. I let the customer decide on lined or unlined for dog collars but the edge coat goes on both anyway. Liners can be any leather you want ,with a lot depending on the dog breed heck i made collars for my Bullies out of two 10oz layers, but they are big dogs.