Stirrup-Cup
Wondrous Item, Common
When a creature riding a mount drinks the cup dry and the cup has a serving left, the rider and the mount it was riding gain this benefit until the next dawn: each can travel for 12 hours before making saving throws for extended travel. Count all travel since the previous dawn toward those hours. After the 12th hour, each must succeed on a Constitution saving throw at the end of every further hour or gain 1 Exhaustion level. The DC still counts from the eighth hour of travel: 10 plus 1 for each hour past 8. Existing Exhaustion levels remain.
Each such completed drink expends one serving, whatever drink was poured into the cup. The cup has eight servings and regains all expended servings at dawn.