This super-strong pond liner from PondXpert is manufactured out of LDPE. It is tough and tear-proof and resistant to UV rays. Despite being so durable it is very flexible and easy to fold into corners if you are considering an intricate pond design. /br> The pond liner is approximately 0.3mm and guaranteed to last 40 years or more. The liner is a tightly stitched core of LDPE which is then laminated on both sides. It is this special production process that means the liner is tearproof. Other liners that we have installed before generally suffer from a weakness of any small nicks/tears \'running\' once the weight of the water is introduced into the pond.