Originally Posted by Jipe

Its the same type of derailleur than the Brompton Advance derailleur but with 10s instead of 4s.

Instead of having a cage with tow pulleys, this derailleur has only one pulley to move the chain, the second pulley is on the separate chain tension arm and is laterally sliding.

Knowing the problems of this kind of derailleur with only 4 cogs, i am afraid that it won't be reliable with 10s because too sensitive to dirt, mud...