Hi Leon,
check this guy's ebay store
http://stores.ebay.com/SMARTASTRONOM...SCOPE-PRODUCTS
He sells dew heater straps for 4" scope for $26 He also has other sizes and dew controllers. I bought 4" and 8" straps with a dew not controller from him but it has not arrived yet. There is a good review about this dew heaters at
http://www.astromart.com/articles/ar...article_id=105 This guy also has a web store somewhere but I don't remember what link is. Try Google if you want to buy from him but don't have ebay account.
Also
Kendrick will start selling this month a new line of dew heaters and controllers. It's called FireLite. It uses a small and quite cheap dew controller.
I wanted to buy this first but since there isn't any specific date when they will be shipped I decided to buy "dew not" solution from the first link.
cheers,
Mike