The special high-carbon steel spring tines with the model no. Upr16 are subject to wear & should be replaced periodically. Contains 2 new springs. Directions for easy spring replacement are contained on the back of the card. 1 set of replacement springs. Refer to model no. Upr16 for power rake replacement springs. No. Areas-12: material: high-carbon steel, Compatible with: model no. Upr-16