It is an original Parker 51 in 12-carat gold-filled cover with East Asian engraving, no copy. Exact identification succeeds via the embossed 'PARKER 51' inside and the typical engraving guide for filling. Asian copies of the Parker 51 are widespread, which is why such finds are first uncertain. The translated characters yield, in combination with the logo, a meaning like 'extent' and 'jade/gemstone' and indicate a special marking. The Parker 51 line counts as very robust and can be operated with nearly any common ink.