The Omni series can be selected depending on the hardness of the lead and writing instrument. The secret to losing this product is two types of ultra-fine particles. Recommended for pencils 2B-6B. Highly adsorptive and wrapped. Eraser; Uses: 2B-6B type; Size: Total length 1.9 x Depth 0.7 x Height 0.4 inches (48 x 19 x 11 mm); Set of 5