Magic Tricks

Alexander Marsh's handling is very good and the clever choreography of envelopes allows for a rather streamlined and efficient modus operandi. On the other hand, the logic of the performance (as demonstrated in the Full Performance section of the video) is faulty in my humble opinion: there is no logic in reading the mind of the participant (and seemingly struggling for it) in order to extract an information that supposedly was known before the effect even started! This effect should be presented either as a prediction - like the original Orville Meyer's TERVIL - OR as a mindreading experiment, but not as BOTH. If the mentalist knew since the start what the participant was going to think of, then there is no point in reading the participant's mind.
As an alternative to Meyer's handling which involved a number of switches, Marsh's handling is very efficient and, as pointed out during the explanation, reinforced by the use of a sealed envelope to produce the prediction.
All in all, a very good variation of the Tervil effect that deserves to be known and used (strictly as a prediction effect in my opinion).