4x AA battery holder 4-battery holder with 6V switch

Wired Bone Conductor Transducer - 8 Ohm 1 Watt
This amazing speaker does not have a movable cone like most From the speakers you've seen, instead, a small metal rod is wrapped with the voice coil.
When the current is driven through the coil, the magnetic field makes a piece of metal expands and contracts, if pressed against a flat surface or cavity makes it a speaker! Often these size transducers are pressed against the jaw or ear bone to turn the skull into a speaker socket.
The effect is a perfect quality sound that comes from your head and no one else can hear it. You can also press it against your elbow bone and stick a finger in your ear to listen to the audio transmitted through your arm!

Voltage Regulator 2% 5V 1.5A TO-220 L7805ACV features:
- Output Type: Fixed
- Voltage Output: 5V
- Manufacturer: ST Microelectronics
- Current Output: 1.5A
- Max input voltage: 35V
- Input voltage min .: 5V
- Operating temperature: 0ºC to + 125ºC
- Encapsulated: TO-220
- Polarity: Positive
- 2% output voltage tolerance (A version)
- Quantity: 1 unit

40x Female-Female Cable 10cm features:
- Length: 10cm
- Quantity: 40 cables
- Dupont female connectors on both ends
- Compatible with 2.54mm male connectors
- High quality and good working conditions
- Easy to install and use

Resistors 2K Ohm 5% 0,25W 1/4W features:
-2 Ohm
-Type: Carbon film
-Tolerance: ±5%
-Power: 0.25W
-Dimensions: 2x7mm

MQ-2 Gas and Smoke Module Sensor Detector Methane Propane Butane LPG features:
- Main chip: MQ-2 flammable gas and smoke sensor and comparator LM393
- Working voltage: 5V
- Current: 150mA
- Digital output: TTL 0/1
- Analog output: analog voltage sensing value
- Quick response features:
- Concentration detection:
  200ppm - 5000ppm LPG, propane
  300ppm - 5000ppm butane
  5000ppm - 20000ppm methane
  300ppm - 5000ppm H2
  100ppm -2000ppm alcohol
- Adjustable sensitivity with the potentiometer
- Size: 32mm x 20mmx 18mm

Power Supply Transformer 220V AC/DC 1A 9V features:
- Input voltage: 100 ~ 240V 50Hz
- Output voltage: DC 9V
- Output current: 1A
- DC connector: 5.5 mm x 2.1 mm
- Cable length: Approx. 90 cm
- Indicator of operation: LED diode