From Pathfinder War of Immortals, which isn't enabled.

Kestros

ITEM 0

UNCOMMON CONCUSSIVE PROPULSIVE

Price 2 gp

Usage held in 1 hand

Bulk L

Category martial

Group sling

Damage 1d6 piercing

Range 40 ft.

Reload 1

The kestros is a type of sling that fires special ammunition with wing-shaped fins and a pointed end. The thongs of the sling are of uneven length, one shorter and one several inches longer, around an open loop to cradle the ammunition as the sling is spun.

Pathfinder War of ImmortalsORC