TWFocus is a lightweight alternative to large and complex unit frame mods, if you just want to be able to see your focus, its target, and its target's target at all times.
TWFocus is a great tool for DPS in 5-man instance runs, because now you can
easily set someone as your 'main assist' and see their target at all times.
No more /assist (name) macros!
TWFocus is also handy for healers in and out of raids, because you can set
a tank as your focus, and immediately see his or her health at a glance.
You'll never have to try to remember where your tank's life bar was amidst
a sea of other unit boxes!
TWFocus will show debuffs on your targets. If you're keeping an enemy
polymorphed, banished or hibernated, Focus will show you when they break
free and need to be controlled - and you can just click on your focus
target to pick them up again!
TWFocus supports Clique. Dispel your focus easily, without ever needing to
switch targets!