Dueler H/L 400 tires in sizes P245/60R18 104H and P245/50R20 102V. According to Tire Rack it is a "Highway All-Season" according to the list here http://www.tirerack.com/tires/bridgestone/bridston.jsp

but clicking it brings up no particulars of the 400 but the Dueler HL series in general seems to have pretty decent tread wear, braking grip and traction. while the numbers are mediocre in the survey results the reviewers seem to really like the snow traction.

 

I guess whatever they can get a good deal on.