The First Tier-4 Wheel.
編輯: Simple MTL
This was perhaps the reason why they were unable to open the secret trove perfectly.
As for Su Han, because he had copied it directly, he had perfectly constructed the key wheel in his body from the very beginning, maximizing that force. That was why he was able to open the secret trove perfectly.
Su Han finally understood why his strength had increased at an unimaginable speed in the past few days. When he faced that tier-7 wizard, even he himself was slightly surprised by his own strength.
Su Han nodded and said, "I have some methods of my own. Thank you for clearing up my doubts."