What is the lining attached to the bottom of a SLR camera?

We all call it "handle". If you search on Baidu or Taobao, you can find many. Different brands and series of camera models require different types of handles. The so-called handle can be understood as a plastic case that wraps more batteries and is more convenient when the camera is shot vertically. The camera body can only install one lithium battery, and the handle can install two lithium batteries and 6 AA (commonly known as AA) batteries. In addition, when the camera is shooting vertically, there is a shutter in the upper right corner of the handle to facilitate focusing and shooting. In actual use, most people use it to show off, because after installing the handle, the camera becomes larger and looks more professional. However, because the SLR camera + lens itself is already very heavy, plus the handle and battery, it will require more physical strength when shooting. It's okay if you play with it on a daily basis, but if it's taken by a professional photographer every day, your wrist will be exhausted. Of course, except for the master level, everyone has a dedicated car to pick them up and an assistant to pick up the equipment. Generally speaking, many photographers do not use the built-in flash on the camera body, so a lithium battery can take about 400-500 photos. Even if you go on a trip, you can take two batteries with you to shoot for a day and go back to the hotel to charge them at night. . Therefore, the handle is generally not used unless there is a special need. If it's cool, it's good to buy a domestic one from Taobao for 300 to 400 RMB; the original one is very expensive.