optional larger voltage regulator
A voltage regulator will burn any provided voltage above the regulator limit into heat. E.G.: 12 Volt input, 5 Volt regulator, 60 mA module consumption will result in a heat loss of (12V-5V) x 0,06A = 420mW.
The small voltage regulator on our boards is usually fine for a continuous voltage supply of 12 Volt. If you want to supply a higher voltage (a car with a running engine has 13,8 Volt) you better choose the optional bigger voltage regulator.