Imperial Pools Nexus NSS003 8' Inside Radius Stairs for Radius Wall with Polymer Open Top. Whatever you want your pool entrance system to be, Imperial has the right one for you. Our steps are the most aesthetically pleasing in the industry, constructed with comfort, durability, strength, and safety in mind, and protected with a Limited Lifetime Warranty. Our vinyl-covered open-top Polymer and Steel Stair Systems extend the pattern of your pool's interior finish onto your steps, creating an uninterrupted, continual, elegant look.