Solvent Based Head Cements are great for building-up layers. These products are thin in viscosity and penetrate deeply into the thread and other tying materials. These come ready to use but can also be thinned with fly head cement thinner. Solvent Based Head Cements dry quickly and will not produce a "shiny" head on flies unless several thin coats are applied. The Solvent Based Head Cements come in clear and black.