JW series screw jack overview: Ability of load: 1.96-980kN Power: 0.25-21kW 1. JWM (Trapezoid screw) JWM (trapezoidal screw) is suitable for low speed and low frequency. Main components: Precision trapezoid screw pair and high precision worm-gears pair. * Economical: Compact design, easy operation, convenient maintenance. * Low speed, low frequency: Be suitable for heavy load, low speed, low service frequency. * Self-lock: Trapezoid screw has self-lock function, it can hold up load without braking device when screw stops traveling. Note: Braking device equipped for self-lock will be of malfunction accidentally when large jolt & impact load occur. 2. JWB (General ball screw) JWB (General ball screw) is suitable for high speed, high frequency and excellent performance. Main components: Precision ball screw pair and high precision worm-gears pair. * High efficiency: Rolling friction improve efficiency greatly, only a little drive power can generate great thrust force. * High speed: Rolling friction speed up travel of screw easily. * Lifetime longer: High precision ball screw can make JWB's lifetime longer by 3 times comparing with JWM. Note; Braking devices or motor with braking devices are necessary when choosing JWB.