Except for the "Ultimate gear crate", all others are spun for purple fish tickets, which you get as rewards for playing spearfishing missions.
After spinning, you get a list of 5 random rewards. The central one is already yours. If you like the two beside it, tap "Get bonus" to get those too. Same with the two on the sides!
If you're looking for the best possible gear, you should aim for the Ultimate crate!