After purchasing a C26 model Randy (Serena), I bought an outdoor thermometer because it didn't have one. However, it was too troublesome to install, and I never even opened the package. Later, I switched to an 80 series Voxy, which comes standard with an outdoor thermometer, so it became completely unnecessary. I don't understand the functions very well, so I'd like to sell it at a low price to someone who knows about it.