Bone Hourglass is a Keepsake that increases the number of encounters items from the Well of Charon will be active for. It is obtained by giving Charon a gift of Nectar at his shop. Its effects can be enhanced by clearing enough encounters with the keepsake equipped.
Unequipping the Bone Hourglass between levels will remove the item duration bonus it grants.
Items from the Well of Charon have durations increased by +4/6/8 Encounters.
From Charon; you share an Unspoken Bond
Only a scant few souls ever earn the favor of the feared boatman.