...Hmm... I was thinking you may be able to get by with one seal, then I thought the LFMC/LNMC would mandate two, but I can find no such requirement. Using one would be dependent on distance from enclosure to CID2-unclassified boundry being max of 11' 6" (18" enclosure to seal... 10' seal to boundry) as the conduit runs and also subject to the no-fitting requirement.