Using these HQ Juicy Prop J40 propellers is easy. Just attach them to your compatible device following the normal installation steps. When using, make sure your device is in good working condition. As for precautions, avoid using them in extreme weather conditions like heavy rain or strong winds. For maintenance, regularly check the propellers for any signs of damage such as cracks or chips. If you notice any issues, replace the propellers immediately. Store them in a dry and cool place when not in use to keep them in good shape.