Super PACs are a variant of the traditional PACs that arose out of Supreme Court case Citizens United vs FEC.
Traditional PACs cannot donate amounts above $5,000 to their chosen candidate, although they can give $15,000 annually to any national party committee and $5,000 to any other PAC.
PACs cannot receive more than $5,000 annually from individuals, corporations, firms, other PACs or national party committees.
Super PACs have no limits in the amount of money they can receive annually, and they can spend unlimited sums to advocate for or advertise against any candidate; and
PACs can donate the money directly to their chosen candidate.
Allegedly Super PACs cannot coordinate with the candidate and are prohibited from donating money directly to political candidates or parties. See also Carey Committee.