Magnets, using the current supply.
Holding electromagnet is powered with voltage of 12 V with power of 4.2 W. It keeps the weight of 180 kg by standard earth acceleration of 9.8 m/s2. The dimensions of the electromagnet are 170 x 40 x 21 mm. Included is a set of mounting screws.
The holding electromagnet powered with voltage of 12 V and a capacity of 8 W. It holds a weight of 20 kg in standard earth acceleration 9.8 m/s2. The body diameter is 40 mm and its height 20 mm, hole with M3 thread is used for mounting.
Module from the Grove are equipped with magnet holding. Holds a mass of 1 kg in standard earth acceleration 9.8 m/S2. Case diameter is 20 mm and its height is 15 mm, for fixing the magnet to the plate that is drilled and tapped M3. Has a digital output, making it compatible with most line modules, including Raspberry Pi and Arduino.