Standby UPS
Protects against 3 of the 9  most common power problems

Standby UPSs primarily protect against power failures, power sags and power surges. This basic protection is necessary in order to prevent damage such as data loss, file corruption, flickering lights, hardware damage, and equipment shutoff.  (Standby) UPSs offer a degree of protection against other power problems and are most commonly used to protect single Equipment.
Basic Type of UPS

Interactive Sine wave UPSs are most effective against (power failures, power sags, power surges, under voltage and over voltage) and offer a degree of protection against other power problems. Some of the damages you risk by not using a Interactive UPS include premature hardware failure, data loss and corruption, data error, keyboard lockup, storage loss and system lockup. Interactive UPSs are recommended for small network systems all the way up to enterprise networking environments.
Interactive simulated Sine wave UPSs same as above but with simulated sine wave output  .Recommend as Mininum protection
(Not for Low Power Factor loads)

Online UPSs protect against all Nine power problems: Online UPSs are comprehensive protection for all of the Nine damaging power problems as well as component stress, burned circuit boards, data crash and program failures. Online UPSs offer the highest level of power protection available and are always recommended for mission critical applications like server farms and hospitals.
Power Protection as easy as 3, 5, 9

Recommend for Best Proctection