Pentax CM50 Range of Centrifugal Pumps, Pentax CM50-125A, CM50-125B, CM50-160A, CM50-160B, CM50-200A, CM50-200B, CM50-200C, CM50-250A, CM50-250B and CM50-250C Pumps. Centrifugal Single Stage Monobloc Pumps Surface Mounted Pumps. Monobloc horizontal centrifugal pumps, constructed to EN 733 standards; widely used in water supplies, pressurisation and fire-fighting systems, cooling, heating, irrigation, industrial and agricultural applications; standard supply with counter-flange.