Add extra protection and peace of mind to your pond, your investment. Increases pond liner life and is quick and easy to install. Protects from sharp objects and prevents ground under liner from over-stretching. Made from 100% polypropylene non-woven material, will not mildew and is resistant to damage from insects and rodents. Material weight: 4.5oz *Width is always 15ft wide. Pieces can be overlapped and come cut to help with placing. How to Determine the Size Underlayment You Should Buy: 1.) Determine the total sq ft of your pond liner: Example 20'x30' = 600 sq ft 2.) Divide the total sq ft of your liner by 15 (this is the width of the rolls they come on): Example 600 sq ft / 15 = 40 Example: You would need to purchase a 15'x40' underlayment
