... are bulge rims of 45 or 60 degrees on the panels, which leaves out connection parts, making it more flexible and ... adaptable.The specifications of water tank panels are 1000mm×1000mm, 1000mm×500mm, 500mm×500mm, the thickness include ... 5mm, 8mm, 10mm, 12mm, 14mm, 16mm. And 5mm panels specially are used for covers. White GRP Water Tank