Click image to view full size image
Hydraulic grab bucket operates with a central cylinder and with own gravity circulation of oil. Without any additional electric supply and consumption of fuel by generators it operates with a battery and a remote control unit, without any motor, pump, electricity supply, cable drum, stabilizer and etc.
link:https://www.kinocranes.sg/grab-bucket/hydraulic-grab-bucket.html
Hydraulic Grab Bucket | Kenancranes