Slates are available in different sizes : 1) 12"x12"(30cm x 30 cm) - 10 to 15 mm thick 2) 16"x16"(40cm x 40 cm) - 10 to 15 mm thick 3) 18"x18"(45 cm x 45 cm) - 12 to 18 mm thick 4) 24"x24" (60 cm x 60 cm) - 12 to 18 mm thick 4) 24"x12"(60 cm x 30 cm) - 12 to 18 mm thick As per requirement custon sizes are available ... NOTE: Slates are natural materials which can have color variation, but we take care to keep the variation to the minimum.