The first photo shows the Flat Beater Blade that comes with the KA, The second photo is the Flex Edge Beater Blade.
The Flex Edge Beater Blade is intended to be used in place of the Flat Beater Blade. It is essentially a Flat Beater Blade with a windshield wiper like flexible blade fitted to one side. The flexible blade is intended to scrape the sides of the bowl and keep the bowl clean. Your mixing process is quicker because you don’t have to keep stopping the mixer to scrape down the sides with a spatula. For those of us who try to scrape the sides of the bowl while the mixer is running, it is both quicker AND safer. At first blush it doesn’t appear that this blade is doing much. It only make contact with a small 11/2” wide portion of the bowl per revolution. Each revolution it cleans off a different section of the bowl. After a dozens or so revolutions the sides are cleaned off. The dough may build back up on the sides, but it just keeps getting cleaned off. When your turn off the mixer, the sides of the bowl a clean from the top of the blade down. This blade seems to trap a little more dough at the bottom point of the blade, but this is minor. The blade is also dish washer safe for easy clean up.
The Flex Edge Beater Blade in action. You can see where sections of the side of the bowl have been swept clean. You will also notice I am using the plastic pouring shield where I am adding ingredients to this dough and some folks said the Flex Edge Beater Blade throws the batter around. I have noticed no difference so far for the types of doughs or batters I make.
For me this blade works as advertised. Most of the recipes I do have the mixer on low speeds and at those speeds they work like a charm. Some folks have reported that at higher speeds, the dough goes flying out of the bowl. As I said this hasn’t been a problem for me, but the first thing I would try is using the splatter shield cover that came with my mixer. There is a third party flexible plastic blade called the Metro Design Beater Blade. This one was $10.00 cheaper and was made of plastic. I saw some videos of it in action vs the KA Flex Edge blade and the results were inconclusive. I didn’t notice a significant difference in how well it cleaned. I did notice less dough clung to the Metro blade when you turned it off. The main thing that disqualified the Metro blade in my eyes was it’s “One size fits all” design. KA makes several versions of their blade to suit their different models and and bowl styles. The phrase “Jack of all trades, master of none” comes to mind. One thing in the Metro Blades favor is dough did not seem to stick to it when you turned the mixer off.