KK Technology
Manufactures the CAM1 capillary anemometer system for imaging and measuring velocity in individual capillaries and determining capillary density.
http://www.kktechnology.com

Microsolv Tech
HPLC Columns, Accessories & Flash Chromatography, autosampler vials, syringe filters, HPLC fittings, LCMS columns by MicroSolv
http://www.microsolvtech.com/

Dr. Tube
Dr.Tube. The specialist in the repair and modification of tube amps. Sale of tubes and components.
http://www.drtube.com/

Hautau
Hautau builds rotating-head tube cutoff lathes, dual-blade tube shears and tube endfinishers. Made in the USA.
http://hautau.com/

Frank's Electron Tube Pages
Vacuum tube, vintage radio and other electronics information. Tube data sheets and pinout.
http://www.tubedata.org/

RadioPistoia by Pierluigi
Radiopistoia Radiocorriere radio a valvole riparazione e restauro radio a valvole
http://www.radiopistoia.com/

World Tube Audio Portal
Here is the biggest tube audio related link list of the world plus forums and newsgroups, tube amplifier collection, tweaking, DIY, Tube Audio Sound Research, many detailed pic's
http://www.worldtubeaudio.com/

Tube database search
From NJ7P great site for tube searches. Very many data sheets and examples, includes application notes for some tube types.
http://hereford.ampr.org/cgi-bin/tube

The Tube CAD Journal
Online-only magazine with technical articles on vacuum tube audio design, tube circuits, speakers, and amps. Previous issues freely available in archives
http://www.tubecad.com/

Sentry Equipment Corporation
Sentry Equipment - sampling systems, sampling equipment, and specialty heat exchangers
http://www.sentry-equip.com/