CPU: 16-bit NEC V30 MZ processor at 3.072 MHz
Internal memory: Built-in EEPROM and 1Kbit RAM for backing up game data.
Screen size (diagonal): 63 mm (2.49 inch)
Color: 8-shade monochrome
Battery life: ~30/40 hours playtime
Audio capabilities: Four digital audio channels, each of which can play sequences of up to 32 4-bit samples, at different volumes and frequencies. Channels 2 to 4 include selectable "voice", "sweep" and "noise" functions respectively. Mixed channels are output via an 8 bit DAC.
Sound output: Mono built-in speaker / Stereo through optional 3.5mm TRS connector (headphone jack) accessory
Sound levels: Loud / medium / mute
Weight (with battery):110 g (3.88 oz)
Cartridge capacity: ROM and/or RAM - maximum 128 Mbit Maximum 1024 Mbit
Ports: Link (accessory) port, cartridge port
Gameplay buttons: X1, X2, X3, X4, Y1, Y2, Y3, Y4, A, B, START & SOUND
Additional inputs: Side-mounted power switch, screen contrast dial
Physical dimensions: 121 mm x 74.3 mm x 24.3 mm
Available colors (physical): Ten available
Source: Wikipedia, "Wonderswan", available under the CC-BY-SA License.