What type of batteries do the counters use and how long do they last?
All TRAFx counters use standard, economical alkaline batteries (e.g., EveryReady, Duracell, etc.). These batteries are sold everywhere and normally cost about $1/each. You can also use lithium batteries for some types of TRAFx counters, but these are normally not necessary and are very expensive: they generally cost about $25/each.