corneal lens lens

reverse variable length coding

variable length

variable length field

variable length window

Variable length don′t cares

adjusting focal length

focal length

focal length calibration

focal length of objective glass

primary focal length

secondary focal length

explosion-proof variable frequency variable speed

function of complex variable complex variable

stator variable voltage variable speed

variable diameter and variable pitch

Variable Frequency Variable Speed

variable frequency variable speed system

Variable Voltage Variable Frequency

anchorage length and lap length