The CASIO SF-3990-GY-w is a rare and retro electronic digital diary with 128KB memory. It is a portable device that allows users to store and organize their information electronically. This model from Casio's vintage computing line is a unique piece that collectors may appreciate for its nostalgic appeal and historical value in the world of digital technology I opened the box myself to show it was working. The batteries weren't installed, so I put them in. It's unused, scratch-free, and in perfect condition.Memory 128KB.Produced in the 1990s.Gray plastic material. I'm also sending the trackable mail.PTT posta.