See more about this article : Master DOC skimmer up to 1057 UsG

Contains two Hydrofoamers Silence 9420.04, recommended for aquariums up to 4,000 litres (1,057 USgal.) of salt water.
Immersion depth from 160 to 270 mm (6.3 to 10.6 in.), dimensions: L410 x B260 x W580mm (L16.1 x W10.2 x H22.8 in.), 230V/50Hz (115V/60Hz) 32 W; water throughput: 2,600 l/h (686 USgal./h), air capacity: 1,700 l/h (449 USgal./h), Skimmer cup volume: 2 litres (.52 USgal.).