General quality is very good. I stick mine back in the small box they came in after use. Have well over 100 hours on my 120 volt model and a lot on a 12 volt version. To me they are the best thing that has happened to nitro engines in a long time. Very rare for me to crank an engine that has not been heated now.

There is a full thread of info about them:

http://www.rctech.net/forum/offroad-...-heat-inc.html

The Deans is on the end that connects to the battery. You will need a female Deans coming from your battery.