Sieve is for use in determining fineness of paint pigment. Its small size and light weight allows it to be weighed with its contents on an analytical balance. National Bureau of Standards Series No. 325. Frame diameter of 3". Depth to cloth, 1.25". Cover or pan not included. Each sieve has an individual serial number. The sieves are manufactured with sieve cloth that has been examined on equipment that is traceable to N.I.S.T. and found to be within stated tolerances. Each sieve comes with a Certificate of Conformance. Stainless steel wire and frame.