P series gear units overview: 
1. Modular design realizes variable combination.
2. Housing is made of cast iron, which improve its rigidity and anti-vibration.
3. Sun and planet gears are processed by cementite and hardening, gears are processed by grinding, which improve the efficiency and lifetime of gear units.
4. Input mode: coaxial input, helical gear input, bevel-helical gear input. 
5. Out put mode: internal involute spline, hollow shaft with shrink disk, external involute spline, solid shaft with flat key.
6. Mounting mode: horizontal vertical, torque-arm.
7. P series sizes 9-34, transmission stage:2,3, ratio:25-4000. 
8. Ratio will be larger in combination with CR, K, R series.