We are a professional manufacturer of drive shafts and universal joints for farm
tractor in China. The shafts we make are six spline, Lemon and threaded hole. 

The sizes are 1# shafts, 4#shafts, 6# shafts and 6# shafts with slip clutches:
1) 1# shaft: 
    a) length: 27" - 50"
    b) Six spline ends: 1-3/8"
    c) Up to 30HP tractors
2) 4# shaft: 
    a) Length: 29" - 53"
    b) Six spline ends: 1-3/8"
    c) Up to 56HP tractors
3) 6# shaft: 
    a) Length: 36" - 56"
    b) Six spline ends
    c) Up to 100HP tractors
4) 6# shaft with slip clutch: 
    a) Length: 36" - 56"
    b) Six spline, Lemon and keyway threaded hole 
    c) Up to 160HP tractors at 1,000rpm