The Irish classics and the subject of a cult worship! This is the “Peterson’s system” invented at the end of 19th century and which made the company world-wide famous. The pipe is from the early new, “republic” era, made most probably in 1950-60s.
The pipe markings are “PETERSON’S \ SYSTEM \ STANDARD”, “MADE IN THE \ REPUBLIC \ OF IRELAND”, “314”. The length is 12.6 cm (4.96″), bowl’s height is 4.5 cm (1.77″). External diameter of the bowl is 3.6 cm (1.42″), internal diameter is 1.8 cm (0.71″). The depth is 3.7 cm (1.46″) and this pipe weights 47 gr. Briar, vulcanite stem, no filter. The chamber has been protected with a break-in coat. The stem has been slightly patched in the button area, you may identify the trace under a bright light.