brand new to Model A`s

[jckbckhm]

so call me ignorant to Model A fords, but i have a question (and i apolagize if this has been asked earlier, couldnt find anything on it...) as to what the purpose(if any) the hand throttle is, other than cruise control. doese it just adjust the idle of the engine or.....? How far off am I? Thanks for any light shed on this. been lookin to buy one but id like to learn as much as possible so i dont look like a total ametuer at the shows haha.