MODELS MK3, MK4, MK5, T35. SIZE 60.80 mm + 030" (0.75 mm) = 61.55 mm. DOUGLAS 348cc (350). COMPRESSION PISTON RINGS (X4). PISTON RING SET. 1 SET OF RINGS FOR 2 CYLINDERS. SCRAPER RINGS (X2). GOOD PERIOD PIECE OF HISTORY OF THE BRITISH MOTORCYCLE ERA.