This guard is similar to High Prime, protecting the upper and inside line, however in Hutton's description it is held even higher up.
In this position the point hangs to the opponent's right hip, while the guard is held at head height. This guard may be even higher than shown in the high prime such that the fencer can look under the shell at the opponent.
It is an excellent guard to withdraw in after an attack.
Hutton does not recommend it as a guard for general use in the attack as it fatigues the shoulder quickly.
See the images below for a high prime parry vs a hanging guard (after Miller, 1737).