Just head over to the gold rat page and send Dustin an email mate, not 9nly does he make them you'd be hard pressed to find someone who understands how they work and common sense answers to questions from the manufacturer like he will give you. He will walk you through any questions you have to give you the most suitable product he has for your needs.
You could try him under his forum name in a search and send him a PM here if you have no luck. His name here is Goldigg@ and can quickly be found in sponser section.
Alternatively he's also on Facebook also under Goldrat Highbankers.
Cheers.