MELISSA & DOUG-Art Essentials: Rainbow Stamp Pad. This oversized pad includes six vibrant colors of washable ink making it perfect for kids’ stamping and art projects. Each individual ink pad measures 2×2-1/8 inches and the overall set is 5×6-1/2 inches. This package contains one Rainbow Stamp Pad. Recommended for ages 4 and up. Conforms to ASTM D4236.