SERIE'S FEATURESRing-Lok access to filter element for "tool-free" servicing.Built-in tooth on Ring-Lok allows you to easily disengage lid.Automatic Air Bleed assures 100% filtration and longer filter cycles.Convenient, easy-measure D.E scoop included with each filter.Eight industry-standard curved grids, all one size. No short grid !Large diameter tank allows a grid spread that covers from 15%-25% more surface area than other leading D.E. filters. This results in s