WHOIS Lookup For Domain Name opt.pf:

This TLD has no whois server, but you can access the
whois database at: https://eservices.mana.pf/whois/publicQuery/registrar

WHOIS Lookup For Similar Domain Names:

opt.com  opt.net  opt.org  opt.cn  opt.com.cn  opt.cc  opt.co  opt.tv  opt.in  opt.de  opt.co.uk  chaobie.com