The Carrera 1/30 Curve Inside Shoulders increase the width of the track and come in a six pack along with two straight end shoulders (1 - right side and 1 - left side), and each shoulder is 3.90 inches wide. This 1/30 Curve Inside Shoulder is made to fit on the inside of the Carrera 1/30 curve track. 1 piece = 30 degrees, and 6 pieces = 180 degrees (half circle). Compatible with Carrera Digital 124, Digital 132 and Evolution slot car race tracks.