Review on Injector Refrigerant Coupler Charger NAKAO by Drew Panah

I could not use the product. The inner piston rod was unscrewed from the end cap instead of pulling the piston into the cylinder. I couldn't unscrew the small end cap to add oil. I tried using the strap holder on the tube and pliers to block the channel on the cap but I couldn't remove the filler cap. Before using the tools, my son and I cut our fingers trying to remove the cap by hand.