I would like to buy 5 phone covers for Asus ZenFone 4 Pro (ZS551KL)

Question from Alessio Lombardi of UK: I would like to buy 5 phone covers for Asus ZenFone 4 Pro (ZS551KL). I’m referring to this:
https://www.duxducis.com/skin-pro-series-case-for-asus-zenfone-4-pro-zs551kl/

Is it out of stock, or can I buy it somewhere?  | Answer: it is end of life.