SOSS® Invisible Hinge model #220SSIC is ideally suited for most types of doors that are 2″ thick. The model #220SSIC is made of 316 stainless steel materials. The SOSS Invisible Closer gives you a closer that is totally invisible from either side when the door is closed. The closure rate is completely adjustable with an allen wrench after installation, and does not require removal of the spring closer. Installation can be either inside the door itself or inside the door jamb. SOSS® Invisible Hinges open a full 180° and are a single action hinge. The Underwriters Laboratories labelled the model #220SSIC SOSS Invisible Hinge can be used on hollow metal, sheet metal, tin clad, steel composite or wood core swinging type fire doors and frames rated up to and including three hours. They can also be used on wood core doors and frames rated up to 20 minutes. Additionally, they can be used on wood/plastic composite doors constructed with Georgia Pacific FS 1 or FS 2 banding for a rating up to and including 90 minutes.