45NRTH utilizes a two-piece construction method to create a reliable and high-performing bicycle tire stud with a concave carbide-aluminum design. The open space and edges created by the large concave crown result in twice the surface area for increased traction and grip. Concave tip for traction, durability, and longevity Aluminum base to save weight Compatible with the 45NRTH stud insertion tool Large stud offers more bite than regular concave stud and less rolling resistance than XL stud Sold in a pack of 25 We design 45NRTH tires for extreme winter cycling applications. We do not recommend this product be used with power assist bikes as the additional torque and system weight can lead to pre-mature casing wear and stud loss.