![2Pcs 220° Wide View Angle Door Viewer Home Security Anti Theft Peephole Adjustable Glass Lens With Back Cover 14/16mm Open Hole|Door Viewers| - AliExpress 2Pcs 220° Wide View Angle Door Viewer Home Security Anti Theft Peephole Adjustable Glass Lens With Back Cover 14/16mm Open Hole|Door Viewers| - AliExpress](https://ae01.alicdn.com/kf/H0b4e5b08be6d4cb3858dffc808e4b02ez/2Pcs-220-Wide-View-Angle-Door-Viewer-Home-Security-Anti-Theft-Peephole-Adjustable-Glass-Lens-With.jpg_Q90.jpg_.webp)
2Pcs 220° Wide View Angle Door Viewer Home Security Anti Theft Peephole Adjustable Glass Lens With Back Cover 14/16mm Open Hole|Door Viewers| - AliExpress
![Peep Hole with Rotating Privacy Cover, 220 Degree Wide View Angle Door Viewer Heavy Duty Solid Brass Peephole for 1-3/8" to 2-1/6" Doors for Home Office Hotel(Gold) Peep Hole with Rotating Privacy Cover, 220 Degree Wide View Angle Door Viewer Heavy Duty Solid Brass Peephole for 1-3/8" to 2-1/6" Doors for Home Office Hotel(Gold)](https://m.media-amazon.com/images/W/IMAGERENDERING_521856-T1/images/I/61Zi-pQu66L.jpg)
Peep Hole with Rotating Privacy Cover, 220 Degree Wide View Angle Door Viewer Heavy Duty Solid Brass Peephole for 1-3/8" to 2-1/6" Doors for Home Office Hotel(Gold)
What is the concept behind the peepholes used in doors? What lens are used which helps us see people standing outside but people standing outside can see only blurred pictures of inside? -
![Peep Hole with Rotating Privacy Cover, 220 Degree Wide View Angle Door Viewer Heavy Duty Solid Brass Peephole for 1-3/8" to 2-1/6" Doors for Home Office Hotel(Silver) - - Amazon.com Peep Hole with Rotating Privacy Cover, 220 Degree Wide View Angle Door Viewer Heavy Duty Solid Brass Peephole for 1-3/8" to 2-1/6" Doors for Home Office Hotel(Silver) - - Amazon.com](https://m.media-amazon.com/images/W/IMAGERENDERING_521856-T1/images/I/61yhhlCOKVL._AC_UF894,1000_QL80_.jpg)
Peep Hole with Rotating Privacy Cover, 220 Degree Wide View Angle Door Viewer Heavy Duty Solid Brass Peephole for 1-3/8" to 2-1/6" Doors for Home Office Hotel(Silver) - - Amazon.com
![Door viewer with 220 Degree Wide Angle Privacy Door viewer Security peek Peephole for Door Thickness 35~60mm, Made of Solid Brass Body and Wide Angle HD Glass Lens(Brushed Silver) - - Amazon.com Door viewer with 220 Degree Wide Angle Privacy Door viewer Security peek Peephole for Door Thickness 35~60mm, Made of Solid Brass Body and Wide Angle HD Glass Lens(Brushed Silver) - - Amazon.com](https://m.media-amazon.com/images/W/IMAGERENDERING_521856-T1/images/I/61vhcuKGArL._AC_UF894,1000_QL80_.jpg)
Door viewer with 220 Degree Wide Angle Privacy Door viewer Security peek Peephole for Door Thickness 35~60mm, Made of Solid Brass Body and Wide Angle HD Glass Lens(Brushed Silver) - - Amazon.com
![220 Degree Adjustable Door Peephole Viewer Wide Angle Eye Spy Sight Hole Glass Lens, Wide Viewing Peephole, Door Viewer - Walmart.com 220 Degree Adjustable Door Peephole Viewer Wide Angle Eye Spy Sight Hole Glass Lens, Wide Viewing Peephole, Door Viewer - Walmart.com](https://i5.walmartimages.com/asr/65c8d08f-7143-4b3a-be37-e66afb25f1e0.36e4b86e8881eee5933b70e19f6e7597.jpeg)
220 Degree Adjustable Door Peephole Viewer Wide Angle Eye Spy Sight Hole Glass Lens, Wide Viewing Peephole, Door Viewer - Walmart.com
![Amazon.com: Zoom Tactical Door Viewer Peephole Reverse with Door Viewer Reverse Door Scope : Tools & Home Improvement Amazon.com: Zoom Tactical Door Viewer Peephole Reverse with Door Viewer Reverse Door Scope : Tools & Home Improvement](https://m.media-amazon.com/images/W/IMAGERENDERING_521856-T1/images/I/51APOFQDS+L._AC_UF894,1000_QL80_.jpg)
Amazon.com: Zoom Tactical Door Viewer Peephole Reverse with Door Viewer Reverse Door Scope : Tools & Home Improvement
![Peephole wide angle, door viewer peephole, solid brass body and wide angle HD glass lens, 220 degree viewing angle, drill hole Ø 16/28mm - Walmart.com Peephole wide angle, door viewer peephole, solid brass body and wide angle HD glass lens, 220 degree viewing angle, drill hole Ø 16/28mm - Walmart.com](https://i5.walmartimages.com/asr/2479cda1-1601-44e4-b30b-1af6adc9500e.c59a729f0d4a5e35f12bb9f5866ba754.jpeg?odnHeight=612&odnWidth=612&odnBg=FFFFFF)