When purchasing 520 master links are there any details other then o-ring or non o-ring? Is strength a detail to watch for or are they all rated the same?
Where is a good place to order from?

this is just me but what ever make and model chain i have is the same type of masterlink i use. if you mix match masterlinks you can run into problems because theres different plate thickness, diff pin lengths, diff pin diameters, diff metals, etc etc. for example if you got a D.I.D 520erv2 chain, i would put that same masterlink back on.