araylist question

Hey, i have a quick question about the following arraylist:

private System.Collections.ArrayList m_workerSocketList = ArrayList.Synchronized(new System.Collections.ArrayList());


I mean, there is an arraylist created which is a 'Synchronized' arraylist...? Could someone please explain me what this is used for..?? It's kinda confusing :(

It is thread-safe instance of array list, thus means that you can access it from more then one thread without need to play with locking or other synchronization stuff.

wow, that's gr8....but it may be a tradeof between using that trick and lock. as i know the lock is the fastest locking mechanism.