This is a command line client that supports SSL and TLS. If you need to do some basic testing of a secure FTP server, these are the commands you must supply:

set ftp:ssl-protect-data true
set ftp:ssl-force true
connect your.ftps.site.org
login userName

It's a bit cumbersome to type all that in, and it's not as if you can supply the directives on the command line - though if you're serious, you can add the set commands to ~/.lftprc