Carlisle Turf Saver Lawn & Garden Tire - 16x6.50-8 by

I have four of these and need to replace with the same however when I measure them they are 18"x 8" fully inflated, how can this be? Incorrect label?

are these tubeless tires or must i also buy tubes?

does this come on the rim already or just the tire itself with no rim?

Ply rating?