?SUCHTHAT vs ?IMPLIES in quickcheck

In Triq, PropEr, Quickcheck in Erlang what is the difference between using a ?SUCHTHAT property and the ?IMPLIES?

From what understand they are both specializations of the values produced by generators.

They are similar:

• ?SUCHTHAT creates a generator, which additionally ensures that each generated value satisfies a constraint.
• ?IMPLIES creates a property, which has an additional possible result, namely "skip". You can use it after all values have been generated.