Spherical Reflection
(Glass Bead Type) Technology

Each glass bead works as follows: An incoming light beam refracts as it passes through the front surface of the glass bead and is reflected off the mirrored surface behind the bead again. The beam then passes back through the front surface and returns toward the light source.

Cube Corner Reflection
(Micro-Prism) Technology

Cube corners are retro-reflective lens elements like glass beads. Each cube corner has three mutually perpendicular refractive surfaces.

An incidental light ray is refracted on each of the three surfaces and is returned to its source parallel to its initial direction. It functions like a ball bouncing into the corner of a room.