9v set up. Has only basic double oring impeller. Motor spins and is the quietest 9v model I tested. Eye works, black door. Faster than other 9vs, maybe x board (shell says xboard). This is Missing the block for second 9v. You might be able to use your backup battery as the spacer. Has Durable plastic shell, hard plastic lid (will crack). Velcro on lid. See pics.