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I believe that you have a hybrid razor with a handle that is a mismatch to the head. That is no big deal as far as the shave goes or the 5 buck cost.

That is a Gillette Tech head which are known...

Any double edge razor blade will fit and work. Some shave better than others but each person id different in what blade works best for them. I am sure Wally World or any drug store may have them.
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