Counterbore plugs are a simple, affordable and convenient way to mask and protect counterbore holes during spray treatment. Their counterbore profile makes them suitable for holes for recessed holes. Produced by Hangon and made of silicone, they can be used for threaded or non-threaded holes. Select one that fits your required hole diameter and simply plug it in.  Use them for holes as small as 2mm up to 12.1mm.