HI ariyodi,
Sorry about the confusion. Sometimes e-tails can post the wrong image for a drive model so it can be hard to determine what a drive is by the picture. The WDBMMA0030HNC model is a retail model number which should be the same as a WD30EFRX. The drives should be the same from what I can with the information that you provided. As for the price difference, drives can come as retail, meaning they have the pretty box, documentation, etc that is included. A drive can also come as a bare drive, which is just the drive in a plain cardboard box with nothing extra. Because of the additional items included in a retail box they may be priced a little higher.
I would verify the compatibility list on Synology’s website for the model of NAS that you purchased. From what I can tell, your NAS should be compatible with the drive that you are looking at: WD30EFRX (WDBMMA0030HNC).
Hope this helped out.
