Danner Manufacturing, Inc. Pro1000 Filter and Falls, Pond Waterfall Box, #02477 Wide spillway for greater water aeration Easily buried to hide filter from sight Includes stepped barb to accommodate 3/4-inch, 1-inch, 1-1/4-inch and 1-1/2-inch tubing Designed to accommodate addition of mechanical or biological filtering for super-clean water 8-inch Opening waterfall width