This is a 8" Steel Vertical. It measures 48" long by 6 5/8" wide.
Verticals can look similar. It is your responsibility to make sure that your pool utilizes a 8 inch frame. It is always a good idea to look through your installation manual and find the packing sheet to see specific part numbers that fit with your pool. This can not be used as a side-vertical on oval pools. However, it can be used along the rounded ends of oval pools.