I've had this stamp for a long time. I sold it in 2005, but bought it back shortly afterwards.
For a plater, this is a pretty cool example of 99R2, Ty III, Scott 21, perforated. At least I think it is.
All of the fun is at the top, bottom and right sides. The left side is the least interesting on this variety, and so getting it centered to the left is good if you don't want to spend $20K on one.