Thailand. (Laotian Civil War). 1971. Stamp-less Air Mail envelope addressed to Bangkok, cancelled by Thailand P.N.A. date stamp '25th June 1971' with framed 'Royal Thai Army Border Patrol' and Censor/ Checked cachet in violet, signed by the Commanding Officer with Bangkok GPO arrival on reverse and slogan postmark dated '27th June.'
Royal Thai Army Troops were on the Thai Laos border as part of 'Operation Phalat' a military offensive of the Laotian Civil War.