Quantitative Filter Papers-Ashless less than 0.010% ash; 4.25 cm, dia; pore size, 20-25µ; 100/box (box of 100) The industry standard for high-purity filtration   Available in a variety of grades and sizes  Quantitative filter papers are the choice for gravimetric analysis. High purity hardened filters have a high wet-strength and are chemical-resistant to handle vacuum filtration or acid/alkali solutions.
 Qualitative filter papers are used for liquid clarifications, analytical separations, or air and water analysis.
 Glass microfiber filter papers are made entirely of borosilicate glass and contain no binders. See our water pollution test papers below. Use up to 550°C (1022°F).
 Prepleated filter papers save you the trouble of folding papers. Papers have more filter surface area for faster filtrations.
Our Whatman filter papers offer you flexibility in filter choice without sacrificing quality. All filters are packaged 100 to a box.
Specifications
Type Whatman 41
Pore size 20-25 µm
Diameter 4.25 cm
Applications Rapid filtration of coarse and gelatinous presipitates
Quantity 100/box

Specifications for Whatman Grade No. 42 Quantitative Filter Paper, Ashless, Whatman 1442-055 :

Diameter, cm:		5.5
Whatman No.:		1442-055
Unit:		Pack of 100
Porosity:		Fine
Flow Rate:		Slow
Particle Retention:		2.5 µm