The "Bass" version which provides a wide-range sound, including a new Bassilator circuit that realistically simulates the resonance of the speaker cabinet and floor.
VOX amPhones Specifications

< Headphones section >

Type: Closed-air dynamic headphones
Driver diameter: 40 mm
Output sound pressure level: 97 dB
Playback frequency range: 20 Hz – 20,000 Hz
Maximum input: 1,000 mV
Impedance: 49 Ω
Cable length: 1.3 m

< Amp section >

Output: 1.4 V (Maximum)
Controls: Dials (Gain, Tone, Volume, Effect), Switch (Standby)
Input Terminals:
*Guitar Input (for “amPhones AC30 / amPhones Lead / amPhones Twin”)
*Bass Input (for “amPhones Bass”)
*AUX Input
Power supply: AAA battery x 2
Battery life: *amPhones AC30, *amPhones Lead, *amPhones Twin
Approximately: 7 hours (Manganese) / 16 hours (Alkaline)
*amPhones Bass
Approximately: 8 hours (Manganese) / 20 hours (Alkaline)

< General section >

Dimensions (W x D x H): 195x 160 x 50 mm / 7.68" x 6.30" x 1.97"
Weight: 230 g / 8.11 oz. (Not Batteries included)
Included items: AAA battery x 2 for trying product, a pug adapter “3.5mm <