Nevit's Hourglass is an item which extends the time you receive bonus experience from Nevit's Blessing.
Basically, when you use the Hourglass, the time remaining on your bonus is paused. When the Hourglass' buff ends, the time continues as normal.
Keep in mind that the buff will end if you die or change your subclass.
The Hourglass is ranged by level.
As with Nevit's Voice, there is a waiting time of 20 hours between each time you can receive one through donations, and the waiting time is shared by all characters on an account.
However, this wait time applies only to each level hour glass.
In other words, you can obtain an Hourglass for your level 25 character and one for your level 55 character without having to wait BUT you would have to wait 20 hours between obtaining one on a level 22 character and a level 26 character.
In addition, once your character moves to a new level range, you don't have to wait to get another Hourglass.
As with Nevit's Voice, if you save up several Hourglasses, you can use them all without waiting.
The range of hourglasses by level and price are as follows:
Levels 1~19: 4,000 Adena
Levels 20~39: 30,000 Adena
Levels 40~51: 110,000 Adena
Levels 52~60: 310,000 Adena
Levels: 61~75: 970,000 Adena
Levels 76~79: 2,160,000 Adena
Levels 80~85: 5,000,000 Adena