I'm mostly a postcard seller. What category do "philatelists" consider to be best for cancels like RPOs, DPOs, military ship cancels, etc. Some are "covers" [envelopes] and some are on postcards.

The Philately-->Cancels--ETA(machine) category seems to be meant for what I would call "meters", but the US site's category seems to be a hodge-podge of cancels--meters, unusual rates, etc. I've put some DPOs on postcards in the Postcard category under the specific State in which the post office was, but I'm not sure RPOs go in the Postcard-->Train category nor do the ship cancels necessarily go in the Postcard-->Boat or Postcard-->military--ship category.

Any suggestions? Anyone have success with these types of postmarks/cancels here at Delcampe?

Just thought of another comment.

In the 'postcard world' dealers often have a 'postal history' section. Delcampe doesn't seem to have a "covers" or "postal history" category. Perhaps this is a US phenomenon. Where do philatelists put paquebot covers for example?