1. from 3 mm grid is more durable and sleek. Being whitened without drilling from the sharp, quick and can be marked! Easy to hold grip with the fatigue. Well of course anchorage of high polymer core use, paper core suitable for reading by OMR! Utilization of eco-friendly recycled materials. ◆ core diameter: 1. 3 mm ◆ internal core: HB Last Friday: brass shaft, knock: play ABS grip: rubber clip: stainless steel Replacement Wick :CH13-HB, erase replacement :Z2-1 N