Battery cover packing for Seiko Twin Quartz 99 series. Compatible with King Quartz, Grand Quartz, and Superior cal. 99. Also compatible with some Lord Quartz 7853 (-5000, 5010, 5020, 5030, 5040, etc., square type). First, I'll say that this is not a genuine part, so it's not a perfect fit. However, unlike other calibers, the battery cover and back cover have a somewhat unique shape, and this part makes good use of that unique shape. For those who purchase this, I will include a manual and explanatory guide created by me in Excel with image files. It's about 10 pages in B5 size. It includes warnings, such as fatal mistakes I made when I was still inexperienced, and how to remove the movement, including how to deal with cases where the battery cover rotates but doesn't come off (there are several patterns). Also, there's a "dark" side to the Twin Quartz series movements that isn't generally known. There are examples where the inside isn't Twin Quartz at all, but the exterior is made to look like Twin Quartz. I'll introduce the details of that as well. Furthermore, I'll explain a special secret technique for opening and removing battery covers from extremely problematic junk items that won't budge even when pried with a coin. It's not a difficult method, but I've never seen it online. Silicone grease will be applied before shipping. Please note that there are rare cases where it may not work well, such as when the case grooves or battery cover tabs are slightly worn, or if the battery cover or back cover is deformed due to previous rust removal with sandpaper (although this is rare). Although unused, I have fitted it to my own parts once for "inspection" before shipping. Please consider it as unused in the sense that it has not been continuously fitted and used on a specific watch. The price is 800 yen per piece. Thank you! Overseas proxy bidders are welcome! We look forward to your business!