This is a Mirage Resin Vertical. It is gray. It measures 52" long by 5 5/8"" wide.
Verticals can look similar. It is your responsibility to make sure that your pool utilizes a Mirage 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.