These are very interesting antique pieces.
They are known as CHOGS. Made from Lignum Vitae, which is a very hard wood.
They were used for tethered horses. When a horse was tethered to the back of a stall by rope, to stop the danger of the horse getting tangled in the rope when lowering and lifting its head, a chog would be placed on the rope to weigh it down and so keep the horse safe.
Extremely tactile and rustic and wonderful as candle holders.
Measurements: 9cm diameter x 8cm high