Hi Joe,
What we think of as "a Polder" is really a generic cooking thermometer/timer that's made in China and then privately labeled and sold by many retailers. Polder was the first and most popular of those retailers. Theirs was called Model 362, and it looks like the picture you see on the
Resources page on the Web site. This page lists a couple of sources, including Polder itself. Most people are still using this one, because they last so long. About all that may be needed are new probes, and those can be ordered from Polder.
Other sources include Radio Shack, Bed Bath & Beyond, Linen & Things, Barbeques Galore, and other kitchen and homes stores and Web sites.
We are now also seeing upgraded versions which have a different, more streamlined look and include additional features like programmable temperature alarms for different types of meat. They can be found in some barbecue stores and at high-end kitchen stores like William Sonoma.
Finally, if you're willing to spend around $90, there is a very slick remote control barbecue thermometer that uses two probes and will transmit the temperature readings to a base station inside your house. It is available from Frontgate.com and Sharperimage.com. Here's a post where I described the product:
http://tvwbb.101inc.com/tvwbubb/Forum1/HTML/000008.html
Regards,
Chrs