Offering artists spectacular results that fire true consistently, Speedball’s Underglazes feature 24 intense colors, that are unmatched in vibrancy. Originally formulated to perform in a wide firing range, 05-6, Speedball’s Underglazes have been successfully fired at Cone 10. Suitable for use on greenware or bisque, each color produces a softer, velvety finish when left unglazed, and intensifies in richness when covered with a clear glaze*. Trusted by some of today’s most well-known and acclaimed ceramic artists. All colors are dinnerware safe when used and fired as directed, are lead-free and carry the AP Seal.