Home Built ROV
Steve Thone's web site with all the information to hand.

The Instructables
Another take beware you could end up starting all sorts of projects looking at this site.

DogCamSport
Sport Cams for all pockets, top end serious broadcast kit used by major TV concerns.

CHDK I've been using this development kit since it was first released. Unlock the power in your Canon Power Shot camera.

Aditnow
Online information resource about mines their details, types, locations, archaeology etc etc Incredible photographic database.

Lektropacks
CAT5 baluns & monitors

Above: The very original "jury rigged" set up which was lowered in Rhiwbach. Photo © Vanoord

Excellent Stuff
UK supplier of the Wise LED Tactical 1500 lumen torch. Title says it all.

UltraLeds.co.uk
An excellent led resource.

Gentles Ltd
James continues to supply me with "bits" of wire that connect cameras to other things!