If you’re asking if the shield has back-EMF protection diodes, the answer is: no, it doesn’t have external protection diodes, as they are built into the H-Bridge. I know that there are people out there that say that this particular chip needs external diodes, but since I first started to use it like 6 years ago I never used them and never burned a chip. Of course, I use small motors that do not exceed the maximum amperage rating. For motors that need twice the current, you can stack another chip on top of the one provided, but you also need a heat sink on them. I’ve seen them stacked and used without external diodes with no problems, so I guess it works, but never actually used them like that myself.