The heavy duty Ultralift is not only an excellent product for counterbalancing windows from 10lbs. to 100lbs.; it also reduces the manual force required to open and close windows by 50%. Standard balances only provide about 40% of the sash weight while the Ultralift lifts 70% of the sash weight. This makes the Ultralift an excellent product to use in nursing homes, schools and windows that are difficult to access. These balances can be used in sashes from 10lbs. to 100lbs. in weight.