The lockout is a good way to train a particular point in the strength curve. It also gets one used to handling heavy weights.
The bar is simply lowered onto the chains,
then locked out. Pins can be used without the chains but the effect is
not quite the same, as the pins tend to stabilize the bar more.
Here our own Clint Gray locks out 365lbs
many thanks to Clint Gray for donating these photos