HS-W22 has the following features
A. No oil cup. Free -grease. Free- machine oil
B. The plunger is made by ceramic material
C. The connecting rod frame is different from others. Please see atatch file
D. Crank shaft is made by forging and then the crank shaft is done with again
E. The new model belongs to Environmentally friendly pumps
F. The v-packing is made by special material, please see attach file