Many people like to use face mask, but people always face the leakage problem.

Therefore: face mask leak guard should be produced to prevent leakage.

The hardest sword is not titanium sword from the vikings. It is the sword made of diamond.

or a sword with a diamond at the tip.

https://www.google.com/search?q=diamond+sword&rlz=1C1ASUT_enCA604CA604&espv=2&biw=1821&bih=774&site=webhp&source=lnms&tbm=isch&sa=X&ved=0CAYQ_AUoAWoVChMIsYWlte6OyQIVApWICh3MpwwM&dpr=0.75#tbm=isch&q=+sword+made+of+diamond&imgrc=FYkMzU8b1OWDuM%3A

“Eliminate all the ways that are leading to a dead end,  in order to choose the one leading to success. ” -the controller of Gods