The Pentel pack of 4 Chalk Marker Pens provides you with a range of vibrant colours; you can choose from red, blue, yellow and white to create your own customised designs. These liquid chalk markers can be used on all non porous surfaces such as glass, blackboards and whiteboards. The chisel tip used on these marker pens has a value activated flow system; this system prevents blobbing or leaking and ensures you get the most out of your liquid chalk markers. Suitable for indoor or outdoor use. 2.0mm line width. Chisel Tip. Colours: Red, Blue, Yellow and White. Pack of 4.