PTO Splined Coupling - Female Spline 1 3/8'' - 21 with - Sparex Part S.15731PTO Splined Coupling Female spline 1 3 8'' 21 with S. 15731 This Sparex Standard Duty PTO Splined Coupling is designed for applications up to 70HP. It features a 1 3 8" female spline with 21 teeth, a length of 95mm (3 3 4"), and an outside diameter of 44. 4mm (1 3 4"). Product Specifications Brand: Sparex Duty: Standard Female spline (ins): 1 3 8 Horse Power: up to 70 Length (ins): 3 3 4 Length (mm): 95 Number of female splines: 21 Outside diameter