Excellent skill for limiting your opponent's actions on their affected turns. It basically only allows your opponent to use spell/trap cards during their affected turns as long as it does not special summon a monster, which means that cards like Ritual Spell cards and Polymerization cannot be activated. This skill will benefit the user if they activate it while they already have monsters on their field and their opponent's front row zone is empty.
Can be used if your LP drops below 1000. Until the end of your opponent's next turn, neither you or your opponent can normal summon or special summon effect monsters, or activate monsters effects. This skill can be used once per duel.
This skill is somewhat situational and risky. The skill requires you to have less than 1000 LP, which is fixed and cannot be changed as far as the game is progressing. Unless your opponent deals effect damage with cards like Restructer Revolution, the risk is still worth taking as it is difficult for beatdown decks to deal damage to you as long as you have wall monsters. Since this skill can only be used once per duel, it is used more often as a last resort.
I finally got it after spending almost 2k keys on Rex. I tested it right away with Gandora on a standard duelist. If you summon Gandora and use it's effect to lower your lp to 1000 or less and then activate the skill, Gandora won't leave the field.