JustNile 4" Vintage Retro Bedside Loud Twin Bell Numeral Desk Table Alarm Clock with Backlight - Colorful Minimalist Design Nostalgic classic-style twin bell alarm clock with back light Twin bell design creates loud alarm function. Flat glass front covers clock face to protect from dust and debris; minimalist design makes time simple and easy to see. Measures 4" in diameter, perfect size for your nightstand/table/desk. Requires 1 AA battery (not included); recommend using carbon-zinc battery