Ashless filter paper
Areas of use include the food industry, agriculture, air pollution monitoring, and gas detection,  be used in qualitative analytical techniques to determine and identify materials, covers a wide range of laboratory applications.
Ashless Filter Papers are made from the highest quality alpha cotton cellulose. One critical step in the manufacturing process of these filter papers is acid washing. All grades are double acid washed in hydrochloric then hydrofluoric acid to reduce levels of SiO2, CaO, and Fe2O3. Ash content less tan 0.01% 
The main function of the quantitative analysis filter paper is to use it for the ashing weighing analysis experiment after filtration. 
Diameter 7/9/11/12.5/15/18cm