Beware there are two rating systems. One seems to be for work load strength and the other is break strength.
ARB's small snatch block is rated - breaking strength 30,000lb. Their higher models is rated at - working load: 19,800lb & breaking strength: 38,500lb
Warn rates their swing away pulley block at 19,000lbs/8618kgs maximum capacity snatch, 24,000 lbs/10886kgs maximum capacity heavy-duty snatch block, and 33,000 lbs maximum capacity heavy-duty snatch block.
Superwinch has theirs too. It's rated to 20,000 lb, Swing Away Pulley Block.
I'd stick with name brands.