Ironsmith
Supplier of tree grates, tree guards, bollards and trench grates for the construction and design industry.
http://ironsmith.cc/

Neenah Foundry Company
Supplier of municipal castings, including manhole frames, lids and grates, trench castings and decorative tree grates.
http://www.nfco.com/

Oberlin Filter Company
Manufactures and distributes range of filtration products and equipment. Includes filter cloths, filter bags and cartridges, air filter units, and selection of new and used filter systems. Offers free analysis of wastewater samples.
http://www.oberlinfilter.com/

Deeter Foundry, Inc.
Since 1945 Deeter Foundry, Inc. has been producing gray iron castings for all segments of the construction industry. Deeter's construction casting product line includes manhole frames and covers, storm sewer inlet frames, grates and curbs, trench grating and tree grates. Deeter also produces a wide variety of special application construction castings. These products are utilized in waste treatment plants, airports, telephone and electrical construction projects.
http://www.deeter.com/

DVP Technologies
Eye Fidelity Tools include the moire filter, graininess filter and JPEG filter.
http://www.dvp.co.il/

Lianda Filter Equipment Co.,Ltd.
Anping Lianda Filter Equipment Co.,Ltd.is an exporter and manufacturer of stainless steel melting filter element, pleated and pipe type,disc filters and filtration wire cloth: over 80 percent of filter elements for export
http://www.lianda-filter.com/

AACplayer
The world's largest development and download repository of Open Source code and applications
http://sourceforge.net/projects/aacplayer/

Filter Specialists, Inc
FSI is the world's most innovative manufacturer of liquid filtration products. We've patented dozens of designs for filter vessels, filter bags and filter cartridges, providing our customers with improved efficiency and significant cost savings.
http://www.fsifilters.com/

MuRa's Filter Meister
Professional filters for Adobe Photoshop and plugin compatible programs such as Paint Shop Pro and available only for the Windows. They are made with Filter Formula. This filter collection is freeware.
http://www.geocities.com/murakuma/mmplugins.html

Filter Solutions
Solutions to all your electrical, IIR, and FIR filter design, synthesis and analysis software needs.
http://www.filter-solutions.com/