The sprayer has easy trigger operation, graduations on the outside and a nozzle that adjusts to give you spray, mist or jet.
Use a mister and spray water on the plants. It is best to spray in the morning and to use room temperature water. Besides raising humidity, misting can discourage spider mite and can reduce the dust on leaves. As a general rule, many plants with fuzzy leaves (African violets, Gloxinia, etc) do no like water on their leaves. These plants will benefit more from one of the other methods of increasing humidity.