The acrylic two way mirror can be installed in either direction, so it can pass the fingernail test. Therefore, you will need other methods to detect a two way mirror.
fingernail-test-comparison-between-standard-mirror-and-acrylic-two-way-mirror
The acrylic two way mirror can be installed in either direction, so it can pass the fingernail test. Therefore, you will need other methods to detect a two way mirror.
