While absolutely no evidence suggests the Celts ever used such a tool, I'd like to think this artifact would meet their approval. Each cord spell is made and cast for you on request, please allow additional time and small variations in the stones used.
The glass vial contains: the Druid sacred herb, golden mistletoe (properly gathered), salt from the Celtic Sea, and 6000 year old Bog Oak from both the approximate time & place of Cath Maige Tuired in Cong, Ireland. Beneath it is Connemara marble.
Next the brown bull leather cord (selected in homage to Donn Cuailnge of the Tain bo Cooley) outlets is knotted in thrice-nine knots, holding a total of nine components, and nine Irish blackthorn beads the ninth of which passes through a County Waterford hagstone which are long said to see into the otherworld. (In reference to the ninth wave liminalility concept in Celtic lore)
The pendulum stone is green, phantom quartz with copper and amethyst. This spell cord is attuned for dedicants to Dark Celtic Gods & Goddesses or for spell work during the dark half of the year.
*also available in Bright Druid, attunement for dedicants of Celtic fire goddesses & spell work during the light half of the year.
Product code: Dark Druid, Spellcord outlets Pendulum