This bilge pump incorporates all the characteristics of the Rule 1500 and 2000 pumps, but with an extra design and construction that will give you years of reliable service. The Rule 3700 gph pump is ideal for heavy work on larger vessels and for commercial use; They are perfect for surfboats, large boats and commercial recreational boats. This pump optimizes the characteristics of an exclusive RULE design to produce a high capacity pump in a compact size.