GEM ORO CUBIC ZIRCONIA MASTER SET FOR DIAMOND COLOR COMPARISON AND GRADING. LARGEST RANGE OF REFERENCE AVAILABLE F,H,J,L,AND N. COMPARISON STONES. STANDARD GIA GRADING SCALE. LASER INSCRIBED COLOR ID ON EACH STONE'S TABLE FOR EASY VIEW. INCLUDES SOLITAIRE RING STONE HOLDERS FOR COMPARING MOUNTED STONES AND PROTECTIVE LEATHERETTE CARRYING POUCH. LIFETIME LIMITED WARRANTY AGAINST COLOR CHANGE. MADE IN THE USA, PATENTS PENDING.