i have a 92 asuna sunnrunner and am wondering about lockers i know they take u through the mud but wat r they exactly? and where can i get them in nova Scotia Canada r they hard to put in or can u diy thanks

Lockers lock your axle differential together so that both tires turn at the same speed.  With open differentials, if one tire looses traction you have no way to get power to the ground, but with a locker your torque goes to the other tire and you keep going.  There are different types.  There are automatic lockers like the lock right or detroit that lock when there's torque and unlock when you coast.  This lets you coast around turns and not chirp your tires but it takes some getting used to driving with them.  Then there are selectable lockers like the ARB Air Locker or Eaton E Locker that you decide when you want them locked or open.  Some are easy to install, some are not.  They help for just about every off road situation.
Hope that helps.

try a search for locker at Ack's FAQ (the link is in my signature, below) for links to web pages on various types of lockers, where to get them and how to install them.

Hope that this helps!

great thanks guys help alot understand now but are a limited slip / positrack  the same as a locker or are they diffrent

A locker only unlocks when no power is be applied like when going around a corner.  A posi or limited slip only locks up when one tire is spinning faster then the other and power is applied.  Basically a locker works a lot better off road then a posi or limited slip.  A posi or limited slip has better road manners though.

A locker only unlocks when no power is be applied like when going around a corner.  A posi or limited slip only locks up when one tire is spinning faster then the other and power is applied.  Basically a locker works a lot better off road then a posi or limited slip.  A posi or limited slip has better road manners though.

awsome thanks all clear now

In my definition, a "posi" or "limited slip" will not fully lock the axles together like a locker does.  A posi or limited slip has clutch plates in the differential and these clutch plates will slip (as they are designed to) and if, for instance, if you have one rear axle tire in the air and one firmly on the ground, the one in the air will be the one that will spin, while the other will have "power" applied to it, it will be at a greatly reduced rate because of the slipping in the clutch plates.
Now in the same situation a locker will "lock up" and effectively become a spool, and you will get 100% drive to both tires, so both tires will spin, no matter if the tires are on the ground or in the air.