The correct rollers for your application depend on your fluid of choice. In most cases, our polyester felt roller covers will offer the best performance. For vanishing oils and for thin stock that is narrower than the overall width of the roller, our polyurethane foam roller covers may be a better choice. Viscosity of the fluid plays a small role but there are other factors to consider. Contact Unist with details on your specific application and fluid type and we'll be happy to make a recomendation!