How do small sprayers do?

Update:22 Dec 2018
Summary:

The homemade sprayer can be modified on the basis of th […]

The homemade sprayer can be modified on the basis of the original sprayer, which is more labor-saving and effective.
If it is completely handmade, it may be a bit rudimentary.
Specific process:
1. Prepare bottles, glass tubes or plastic tubes, and pumping things like syringes.
2. Seal the bottle with a lid and insert two tubes, one for the nozzle and one for the syringe.
3. Pour an appropriate amount of liquid into the bottle, clamp the nozzle, pressurize with a syringe, and then open the nozzle to spray.