Where can you buy the iPhone 5S metal clip that holds the flex cable down (replacement part)

Can someone link me to where I can get one of these clips or tell me what shop will sell them asap cause I just lost mine when I was replacing my screen 😟. I've looked everywhere online for where to buy them but I don't even know what it's proper name is, also is it actually necessary because I don't know if it's safe to use my phone without it; it was obviously put there for a reason?