Guides
Buying guides and product knowledge, written by the ABTI factory.
- Door Viewer (Peephole) Buying Guide: Lens, Material, Door Thickness and Fire Rating
Lens, material, door thickness and UL fire rating — explained once, by a door viewer factory.
- What Is UL Fire Certification, and Why Do Fire Door Viewers Need It?
Who UL is, what its marks mean, what a fire door viewer is tested for, and why the UL Mark is trusted.
- How to Tell Whether a UL Certification Is Real: Verify a Fire Door Viewer in Three Steps
Three steps to check a fire door viewer's UL certification yourself, and the common warning signs of a fake.
- ABTI's UL Fire Certification and Model Cross-Reference
UL File Number R13709, the listed models, and how they map to our website models, all in one place.