T-2's are a level below Primes.  They make good 2nds in a Tower and good backups to a Prime.

T-2's are telepaths and  telekinetics and any other combo of Talent but may be stronger in one talent over another, but the major difference is they lack the strength and length a Prime does.

A T-2 can run a Tower but usually two high talents are required to do close to the job a T-1 can.  The best T-2's are twins, siblings or two that compliment each others abilities where one can path or port better than the other.  

Sometimes you will find a T-2 rating for clairvoyants, finders and empaths.