Aluminum flanged construction, holds two 4-1/2” fans in 3 spacesFan panels accommodate all standard 4-1/2” fans. 3 rackspaces (5-1/4”) high, they are made from 16-gauge flanged aluminum. Offered in a black textured powder coat finish.Fan panel holds two 4-1/2” fans in three rackspacesAluminum flanged constructionBlack powder coat finish