Series 1310 is the volume light-duty size, used across domestic light trucks, vans and a great deal of performance work. A transmission yoke slides onto the splined output of the transmission or transfer case and carries the front joint of the driveshaft.
Count the splines on the output shaft and measure across the spline tips. The same series serves many different spline configurations.
The transmission yoke is the driveline component that engages the gearbox output spline. On many vehicles it also acts as the slip member, allowing the shaft to change length as the suspension moves, in which case the seal surface and the yoke length both matter alongside the spline data.
Series determines the u-joint the yoke accepts. Spline count and spline diameter determine which output shaft it will actually go onto. Both have to match.