The contractor paintbrush series incorporates high performance filaments, knot and ferrule construction. Will work with all coatings including oils, stains, enamels, varnishes and latex paint. PBT, polybutylene terephthalate, is a nylon quality filament, solid, round and easily tapered. This shape is the best for wicking or allowing paint to travel quickly down the filament to the surface. An acid dipping process provides flagging at the tip for the best coverage and transfer of paint to the surface.