LMZNXCZ 3 Way Mirror for Self Hair Cutting,360 Haircuts Mirror Men for Barber Use Tools,to See Back of Head,Tri Fold Mirror with Portable Height Adjustable Telescoping Hooks

3 way mirror basic principle and what advantages does it have over single-sided mirror?The three way mirror is a combination of three single mirrors through a rotary joint, two of which can be flipped...