Mayco Underglaze - UG 206 - Fire Engine Red - 2 Ounce Jar Underglazes are a staple for many ceramic artists. Mayco Underglazes are highly versatile  use for complete coverage or in design, apply to clay or bisque. Serves equally well to a student starting off or a seasoned artist working on a gallery. Fires from cone 04 to cone 10. AP Certified Non-Toxic. Made in USA.