A spool has no moving parts....the ring gear bolts to it and the axles go in the sides and it locks both axles full time. Ideal for drag racing, bad for taking turns as the inside wheel will scrub.
Locker....locks both axles under acceleration, in cornering it unlocks the inside wheel which will just freewheel, while the outside wheel gets the power.
Differential applies power equally to each wheel unless one slips, then it transfers power to the one with grip. Both wheels drive through corners at different rates.
Open differential drives both until one loses grip, then the one w/o grip gets all the power.
Locker....locks both axles under acceleration, in cornering it unlocks the inside wheel which will just freewheel, while the outside wheel gets the power.
Differential applies power equally to each wheel unless one slips, then it transfers power to the one with grip. Both wheels drive through corners at different rates.
Open differential drives both until one loses grip, then the one w/o grip gets all the power.