Auction Series 257-264 in Zurich Day 4

Coastal Ships - Helsingfors Area - Skärgårds Trafik Aktiebolag (STAB) 1886: 10 penni chrome-yellow & blue, Stone IV, perf. 11½, a used example tied by 'honeycomb' network handstamp in violet on 1888 10 p. rose on buff postal stationery card used from Helsingfors (July 3) to Thusby, carried on the S.S. Thyra. A rare and most attractive usage.
Catalogue 261: Stamp Issuing Steamship Companies