SW tees have two types:Equal and Reducing.SW fittings have same ranges of size(1/8”-4”) and pressures(2000lb,3000lb,6000lb,9000lb).Class 3000 is the most common used among these pressures.Class 3000 can be labeled as 3M,where M means 1000,class 3000 fittings can withstand up to 3000 PSI.