The larger ones are 1 & 7/8" OD. Mine is 1.75" OD. I need to check SCLLR's website for the requirement. It doesnt seem like much but it is noticeable.
KRS 322.340 requires every licensee to have an embossed metallic seal or a rubber stamp. Samples are depicted above. The preferred sizes are 1 3/8? for the engineering seal or stamp (maximum size of 1 5/8?) and 1 1/4? for the surveying seal or stamp (maximum size 1 1/2?).
I got my first seal from Engineeringseals.com and it hass already fallen apart. Only 3 months of use. Its just some sort of plastic. I orderd a new one from some corporate supply company its brass and plastic imbossers, much better.