What is a Blade guard?

Blade guard

A blade guard covers the top of the blade━ you should never operate a table saw unless this guard is correctly  in position. An extraction system sits on top of the blade guard to carry away excess dust.

What is a Isolating switch?

Isolating switch      

All table saws should have an isolating switch.
This is used to disconnect, or isolate, the saw
from its power source. Once the machine has
been isolated, you are safe to make adjustments
or carry out repairs.