Imperial USA TH1100 Series Mortise Cylinder 5/16” Stamped Trim Ring

It is a spacer collar that sits between the face of the mortise cylinder and the door or lock face. The TH1100-TR2 is a stamped hollow collar 5/16 inch thick, so it takes up 5/16 inch of the cylinder's threaded length. Use it when the cylinder threads too deep and the face sits below the door surface, or when you need the cylinder face flush and protected rather than recessed.

No. It is cut for a mortise cylinder only, which is the threaded type that screws into the lock case. Rim cylinders mount from the inside face with a backplate and machine screws and take no collar of this kind, and key-in-knob cylinders sit inside the knob. If the cylinder in your hand has threads around its body, this ring fits it; if it has a flat back with a tailpiece and screw holes, it does not.

Other way around. A collar adds thickness behind the cylinder head, so it pushes the cylinder further OUT of the door. If your new cylinder is standing proud of the face, you need a shorter cylinder, not a spacer ring. Reach for the TH1100-TR2 when the cylinder face sits recessed below the door and you want to pack it out by 5/16 inch.

Two: AL aluminum and DU duranodic. Aluminum matches clear anodized storefront, which is the most common finish on commercial glass front entries. Duranodic is the dark bronze anodized look, so that is the one for bronze storefront framing. Match the collar to the door frame rather than the lock, since it sits against the face and reads as part of the door.

You can run a mortise cylinder without a collar when it threads in to the correct depth on its own. The collar earns its place in two situations: the cylinder bottoms out before the face is flush and leaves a recess, or you want to close the gap around the cylinder so a wrench cannot get a grip on the body. If you are ordering a cylinder for a new opening, buy the collar with it, since the depth is not something you can judge until the cylinder is in the lock.

It is a commercial door hardware part, and stamped hollow construction is what that means in practice: a formed metal ring rather than a solid machined one, standard for trim on commercial storefront and mortise applications. Stamped hollow rings are lighter and thinner-walled than cast collars, which is fine for a trim ring since the cylinder threads and the lock case carry the load, not the collar.