It's a different sort of limited-slip diff, the difference being that there is no gradual slipping that you have with a limited-slip diff that allows the inside wheel to turn slower than the outside.
With a detroit locker if you are on the power the diff is basically a spool.
If you have seen any sort of muscle car going very slowly (say 5km/hr) and turning tightly and the back of the car is shaking and jerking that usually means it has a locker type diff.