WRITING BOARDS HAVING GLAZED

Brand	Owner	Address	Description
CONTEMPO	Beckley-Cardy Company	Chicago IL	Writing Boards Having a Glazed Non-Porous Marking Surface, Adaptable for Use with Easels or as Wall Mounted Units, Marketed and Distributed by Office Supply Equipment Wholesalers and Dealers and School Supply Distributors;
	Where the owner name is not linked, that owner no longer owns the brand

Technical Examples

A mechanical acoustic filter is formed of boards made by using erosion etching. The filter may be used in electric condenser microphones. The filter may be made of one or a plurality of boards each being made by erosion etching according to different requirements. The boards can be printed circuit boards, ply boards, or of other materials. Every etched board has corresponding paths, which after the boards are assembled, form an acoustic filtering path that not only can extend the length of the path to filter out high frequency noise more efficiently, but also can reduce the entire volume of the microphone assembly.