Email format error
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6-20 characters(letters plus numbers only)
The password is inconsistent
Email format error
Email cannot be empty
Email does not exist
6-20 characters(letters plus numbers only)
The password is inconsistent
The ball valve can be divided into two types: ball type and ballless type. The difference lies in that in ball type, the central hole of the valve core has a sliding V-shaped groove; in balleless type, it does not have such grooves. Both have their advantages and disadvantages.