The Ultimate Pond Lining System was launched by Blagdon in 2011. It’s aim was to take the worry out of choosing incorrectly sized pond liner underlay by putting the liner and the underlay in one bag. The liner in this pack is a popular size of 4x3m (13′ x 10′) while the underlay is slightly larger to allow overlap at 4.4×3.4m (14’4″ x 11’2″). The thick (0.5mm) PVC Liner is guaranteed for life when used with the thick underlay supplied.