The most important standard for accessing the value of a tower of time was its efficiency per unit time.
Comparing the tower of time that Zhang Tie accessed in Waii Subcontinent with the current towers of time in the Dongtian of Great Wilderness Sect, the first one could be used for 15 years per time while the second ones could be used for 20 years. Whereas, the first one needed 6 decades to recover its energy during which period the towers of time in the Dongtian of Great Wilderness Sect could be used for 6 times, namely they could provide 120 years for cultivation, indicating that the efficiency of the latter ones was 8 times that of the first one. Of course, the latter ones were more precious.
Nevertheless, there were 28 such precious towers of time in the Dongtian of Great Wilderness Sect.
Even Zhang Tie became speechless when he thought that such a great sect with such rich resources was finally exterminated by other forces.
