Diego uses 4 different knives in the show, and a 5th that he has but does not use. They are the United Cutlery Lightning Bolt’s, Gil Hibben Competition’s, and the United Cutlery M48 Stinger’s, which he switches out for another knife that I was not able to find the exact name of, but it looks like a pretty basic military knife. He also wears some standard looking throwing spikes on his wrist, like in the photo you posted.