Glass bead tapes use microscopic glass spheres to bend and reflect light back to the light source. Glass bead tapes are about 30% efficient. This is a disadvantage.
However, there are three advantages that glass bead tape has over most prismatic tapes.
Firstly, glass bead reflective tapes are much more affordable. This is because they are simpler to manufacture. Secondly, most glass bead tapes are CAD cuttable meaning that you can cut letters, number and designs out of the tape and create reflective signs or graphics. Thirdly, glass bead tapes reflect light back at wider angles.