BioGuard Smart Shield - 1 Qt. Brand_Big Green Egg Your filter is the hardest-working

Your filter is the hardest-working part of your spa — it's constantly pulling contaminants out of the water

Length is what separates them: 4-5/8 inches for this C-4401

Detachable propane gas burner

Hard water

Diameters: 5" x 8"

BioGuard Smart Shield - 1 Qt. Brand_Big Green Egg Your filter is the hardest-workingBioGuard Smart Shield Overview BioGuard Smart Shield is the ultimate in pool water conservation. This product reduces water evaporation, helping to conserve water and preserve heat. A single application last up to 30 days. What's in the Box 1 x BioGuard Smart Shield 1 Qt. Features Preserves water temperature. Conserves water lost due to evaporation. Directions Shake bottle before using. With the pump running, add 8 fl oz per 15,000 gallons of water.