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These are the components you need to fit an HDD/SSD into your Cooler Master case.
You already have the cage, so look for the other components you need. In your image, the existing HDD is on a mounting bracket. You need a compatible one of those.
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Your photo doesn't appear to contain a hard drive cage. You've provided the manufacturer name, so I used "cooler master hard drive locks" which returned a number of useful links. It appears that Cooler Master has different versions for the different model numbers.
There's a number of videos showing how to remove and install the locks, but your question is what they are called.
I would suggest to use your model number along with the above search terms, to reduce the number of false links on the journey to find the correct model.
I would have provided at least one link but the model variations are quite numerous.
1what is your cases model number? that should help narrow it down. – Keltari – 2018-10-14T14:22:16.740