These are flexible metallised plastic plane mirrors.
They can be easily cut with a scissors or a sharp knife.
They are safe to use.
They come in packs of 10.
They are available in different sizes:
100 × 150 mm.
50 × 100 mm.
Any size can be fabricated as per one's requirement.
These plastic mirrors are great for student use when learning about light, symmetry, reflections, etc. Try taping them together at right angles for multiple reflections.
They even form for a fun element when used for mirror writing.
It allows students to observe insects and other small creatures etc. in detail.