Differences Among Different LHG harmonic reducers:
* LHT-I: use uni-body type wave generator
* LHT-II: cross slider type wave generator
* LHT-III: large bore with a hollow hole
* LHT-IV: shaft input type
* LHT-V: Simple type
* LHT-I: use uni-body type wave generator
* LHT-II: cross slider type wave generator
* LHT-III: large bore with a hollow hole
* LHT-IV: shaft input type
* LHT-V: Simple type