The following hardware are some of the most popular items:
Haptic feedback is the physical sensations associated with the aircraft in the game. There are a number of items that may produce levels of haptic feedback depending upon their implementation. These pieces of equipment normally function through software, but in in the simplest form can also run directly from the games sound output.
The ButtKicker is a sonic transducer like the centre of a loud speaker without the cone. Often working through a software package which allows different aircraft action (firing guns, gear transition etc.) to be vibration to the transducer which is attached by a bracket attached to the seat.
Woojer Vest is a backpack with a harness that is either connected via a USB or audio lead to the sound output of the game. The mini transducers provide vibration to the back and chest in response to game sounds. It also feels much like wearing aircrew Lifejacket.
Seat pads, like the HF8 Haptic Gaming Pad or Jet Seat, are seat cushions with mini transducers that also react to either game sound out game interface software outputs. These pass the vibrations to the seat and back.