The extremely popular 10" Filtering Waterfall Weir creates a breathtaking 10" curtain of falling water, while offering supplemental bio-mechanical filtration that supports the growth of beneficial bacteria. Manufactured with a super-strong injection molded housing unit, this exceptional waterfall weir creates a professional waterfall effortlessly, and is easy to retrofit to existing ponds. This product is rated for pump flows up to 1200 gallons per hour.