Kickers and slingshots are rubber pads which propel the ball away upon impact, like bumpers, but are usually a horizontal side of a wall. Every recent pinball machine includes slingshots to the upper left and upper right of the lowest set of flippers; older games used more experimental arrangements. They operate similarly to pop bumpers, with a switch on each side of a solenoid-operated lever arm in a typical arrangement. The switches are closed by ball contact with the rubber on the face of the kicker and this activates the solenoid.
Early pinball machines typically had full solenoid current passing through trigger switches for all types of solenoids, from kickers to pop bumpers to the flippers themselves. This caused arcing across switch contacts and rapid contact fouling and failure. As electronics were gradually implemented in pinball design, solenoids began to be switched by power transistors under software control to lower switch voltage and current, vastly extend switch service lifetime, and add flexibility to game design.
As an example, some later machines had flippers that could be operated independently of the flipper button by the machine's software. The upper-left flipper during Thing Flips on The Addams Family pinball machine triggers automatically a brief moment after the ball passes an optical sensor just above the flipper.
The smaller, lower-powered solenoids were first to be transistorized, followed later by the higher-current solenoids as the price, performance, and reliability of power transistors improved over the years.