Aluminium Flat bore covers are custom made to the size of your concrete liner upto 1200mm. Please specify exterior diametre on order notes. Note this cover does not come with an undering. The flat cover is 5mm thick Aluminium. It is designed to take pedestrian traffic. The Aluminium flat covers are light and may require the locking down option if you have children. If you have a ladder which comes over the top of your concrete liner or high pipes please notify us so we can alter the cover to fit at an extra cost. Aluminium can not be used for cars.