Protects against high voltage, brown-outs and voltage dips.
High power (over-voltage) will certainly damage any electrical or electronic equipment.
The Guard protects your equipment by disconnecting the power when it goes above un-acceptable level.
The guard safeguards short term and long term damage to ensure higher efficiency from your appliances.
30 seconds start-up delay is built-in to ensure stability of the power supply, and ensure the appliance is not switched on-off repeatbly during fluctuations nor is it subjected to a massive surge normally experienced when power returns after power cuts.