The following information was taken from Shell’s official site.

Shell Rotella® T Triple Protection Heavy Duty Engine Oil
Shell Rotella® T Triple Protection® Heavy Duty Engine Oil provides triple action to help control wear, deposits and emissions to continuously adapt to the needs of your engine for protection in on- and off-highway applications.
 
Shell Rotella® T5 Synthetic Blend Technology Heavy Duty Engine Oil
Shell Rotella® T5 Synthetic Blend Heavy Duty Engine Oil combines synthetic blend base oils and advanced additives to deliver excellent protection, even at low temperatures where the enhanced cold-flow properties help protect your engine
 
Shell Rotella® T6 Full Synthetic Heavy Duty Engine Oil
Shell Rotella® T6 Full Synthetic Heavy Duty Engine Oil is our hardest working engine oil yet, with improved protection in extreme temperatures. It gives you the engine cleanliness and wear protection you expect from Shell Rotella®. And up to 1.5% in fuel economy savings.*