Liquid chalk markers for venues and costs: 

the most appropriate in the audio-visual equipment room, meeting rooms, kindergartens, lecture theaters, academic halls, training rooms, classrooms, training courses and other places; smooth flat reflective (green, white or color) Metallic blackboards can be used directly; metal blackboards, ground glass blackboards or other blackboards that do not meet this requirement can also be used with liquid chalk after being treated and coated.

 The normal cost of liquid chalk and dry chalk in fact almost the same cost of use, but the initial use of unskilled, the cost may be a little higher just.