Dry Erase Marker InkSize & Spec.:2.5ml per bottle, 12 bottles per boxMaterial: PPSpec. 1:Twist top to open, add ink by dipping to marker tampon, designed for 1-time usageSpec. 2:1 bottle to refill 1 "nearly empty" marker, stop dipping if the tampon is full of inkSpec. 3:For all Deli Black r..