Screw top-lid (the larger side) to screw Firebreaker/Paramerotic.
Apply water-based lubricants first. Please do not apply silicone nor oil based lubricants.
Screw bottom-lid (the smaller side) to adjust ventilation. Your thrust would meet more resistance the less amount of air you let in, making it like sucking in.
After use
Screw the sleeve out gently.
Clean with water. Don’t apply soapy detergent.
Dry in the shade with good ventilation.
After the sleeve thoroughly gone dry, screw it gently back into the shell.