For sale, Dandanator Mini 2.1, built to a high standard, fully tested and ready to go. The unit has had the modification required for it to work with a Multiply microSD device (see https://github.com/mad3001/Multiply) ... Note: Multiply is a separate device,  sellers of which can be found of Ebay.

The ZX Dandanator! Mini is a game cartridge for Spectrum computers.

It’s a hardware external memory (eeprom) peripheral that aims to be a platform for developing and releasing cartridge games and also serves as a Z80/SNA/TAP/Rom game snapshot loader.

It adds some extra functionality like a poke/trainer library, external test rom, 128k game loading, game compression, load screen freezing or Ramjet3 emulation. Its contents can be changed from the spectrum itself via Audio, Serial connection or using a Divide-like interface. Version 2 also includes a Kempston Joystick interface.

There is a basic API to configure and operate the board by sending commands from the Spectrum computer, making the ZX Dandanator! Mini a very flexible solution for several uses such as multiload game delivery or external interface hardware emulation (limited).

Features

• 512k of fast access memory, enabling multilevel game development that offer a console-like experience.
• Instant load of games by a simple menu.
• Games & Programs can be changed from the PC with no extra hardware via audio or with a serial connection or by using a divide/divmmc.
• From V2.0: Kempston Joystick interface onboard
• No need for configuration. It works in any Spectrum computer, from 48k to +3 and most of the clones, including ZXNext and Harlequin.
• Diagnostics program installed. 
• Supports 48k and 128k SNA & Z80 snapshots compressed/uncompressed as well as 16k ROM images. Also supports TAP files and MLD multiload games with progress-save in the cartridge.
• POK compatible trainer library for included games. Games can be launched with any number of enabled or disabled trainers as selected by a spectrum menu.
• Option to freeze loading screen until a keypress or for some seconds
• EDGE connector pass-through allowing to connect other peripherals (yes, Dandanators mini can be stacked ;) )
• It can stay plugged and deactivated. No need to unplug it to use your Spectrum for something different.
• Automatic shutdown if another peripheral wants to take control of the ROM space.
• Management software for Windows, MacOS y Linux to create, transfer and organize your games.
• Emulated as peripheral in release 4.2 of ZesarUX  and in Es.pectrum newest version
• Can be used as a CP/M plug&play system and “Hard Disk” of 460Kb+ for any +2A/B or +3 Model
• You can pause any game by pressing a button
• You can create your own game snapshots from the spectrum

The official Dandanator site can be viewed here: http://www.dandare.es/Proyectos_Dandare/ZX_Dandanator%21_Mini_EN.html