Like its name implies, this mini recorder works on Solar energy, so you never have to worry about changing batteries again. Models Solar are produced in a plastic case. We have the following varieties of model Solar: Solar-140, Solar-280, Solar-560, Solar-1120 (digits show maximum recording length in minutes). Key specifications & features: Dimensions — 28x66x7,5 mm; Weight — 15 g; Voice storage capacity — up to 140/280/560/1120 min; Battery life (in the dark): recording — 8 hrs, stand-by — 1.5 months; Battery type: Solar battery and Li-Ion Rechargeable battery LIR2430; Built-in FLASH memory size: Solar-140 — 16 MBytes; Solar-280 - 32 MBytes; Solar-560 - 64 MBytes; Solar-1120