You know, these little Acu-rites don't even show a model# on the case....I did find it on the web though...model 00648.
I have had a couple other members wonder about them in the past as well. I get them @ our local hardware store for $22.49/ea.
It is a count-up timer/time of day switchable mode with temp sensor reading. The timer will go to 24 hours, if I remember correctly...dang, that would be a LONG smoke! LOL!!!!!!!
You've got a lucky family just to have you thinking about doing a rib roast for them...that would be a dinner to remember...
I guess I have been cranking out some pretty serious smoke lately...never really thought about it 'til you mentioned it...maybe that's why I don't really feel like doing very much on my only day off this week (Wednesday). We've gotten buried @ work with the year-end coming up, so I'm working 5 days on, 1 day off.
Anyway, if I come up with another new idea or something I haven't tried doing yet, you'll know soon after it starts! LOL!!!
You may want to check out this link...just found it right now, on sale:http://www.partshelf.com/ci00648.html
Good luck & happy smokes!!!!!!!