Found new owner
The pipe has stamping of two famous and legendary American manufacturers. But it's not a mistake: since 1953 Dr. Grabow company was merged with Henry Leonard & Thomas Inc. All further owners (United States Tobacco company, Lane Ltd., IPAL) continued to produce the popular Royalton series until our days. The pipe was very lightly smoked (perhaps once or twice) and has a really attractive straight grain.
The pipe markings are "HLT \ Royalton", "DR.GRABOW \ IMPORTED BRIAR". The length is 14.3 cm, bowl's hight is 4.1 cm. External diameter of the bowl is 3.7 cm, internal diameter is 2.0 cm. The depth is 3.2 cm and this pipe weights 37 gr. Briar, acrylic stem, 6 mm filter.