"Peperoncino" (one P) is simply the generic Italian name for all kinds of piquant chile peppers (and some rare specialty non-piquant red peppers) that become red when dried. There are many varieties in a wide range of sizes and degrees of piquancy, though most are far milder than comparable peppers in, say, Mexico or India. The hottest are probably from Calabria, where the cult of the peperoncino is highly developed. Some peperoncini sold in Italy are imported from Africa -- I think mainly the smallest size. Most people either grow them or buy them fresh in late summer/early fall and dry them at home for use throughout the year. So, to get to your problem: what does it say on the package? and in any case, you will probably be happy with any Italian peperoncino.
Don't know if you are in the US or if Calabrian would do, but here's a start: