Singlefin
iPrism - Monitor and Report on Internet use. iPrism is the #1 Web filtering appliance. iPrism utilizes iGuard the top url filtering database for internet content filtering.
http://www.singlefin.net

CyberGuard
ICSA and NSA certified Unixware and NT-based filtering firewall. Offers static packet filtering, dynamic packet filtering (stateful inspection) and proxy gateway (smart proxies).
http://www.cyberguard.com/

Croft Engineering Services
Filter manufacturers, Woven Wire Mesh and Perforated plate stockholders, Croft Engineering Services, based in Warrington
http://www.filters.co.uk/

New Look Enterprises
manufacturers of FRP moulded components, RECRON 3s, RECRON 3s fibres, specialize in mould making for the automobile, packaging and construction industries, FINOLEX corrugated/plain PVC sheets, FINOPAQUE sheets, FINLIGHT range of foamed PVC sheets, FINROOF range of corrugated sheets, leading manufacturers of Fiberglass roofing sheets, FRP manufacturers,distributors for Short - cut polyester staple fibre, india
http://www.newlookenterprises.com/

Visual Dorp Filter
DORP - Home of Object Oriented Filtering for Visual FoxPro and SQL developers.DORP-VDF objects are set of date-centric filtering objects and provided to help speed the process of filtering application development.VCX library for VFP8,VFP9 development views and reports.Advice, tips, sample code, downloads.
http://www.dorp-vdf.com

Safer Path Internet
Dialup access with web filtering or add filtering to your existing connection.
http://www.saferpath.com/

SpamEater Pro
Email filtering system that can automatically receive periodic updates to its filtering rules.
http://www.hms.com/spameater.asp

NetMail
Email client. Full-featured e-mail client designed for e-business
http://www.softwarea.com/netmail.htm

HWG Filtering FAQ (Windows, Mac, Unix)
The HTML Writers' Guild's FAQ sheet about mail filtering systems (multiple platforms)
http://www.hwg.org/resources/faqs/filterFAQ.html

DansGuardian
Offers phrase matching, url filtering and PICS filtering. News, FAQ, mailing list, screenshots. [Unix, Linux, BSD]
http://dansguardian.org/