Sodium perborate is an oxydant.

Sodium perborate

Search in your country an office of Merck Millipore or a retailer of chemical products.
The catalog number is 1065609050 for 50 kg sodium perborate.

Many types of detergents contain sodium borate or perborate.

Very similar, but not identical. The term "hydrate" means that there are water molecules associated with the sodium perborate. In the first case, the "tri" means that there are 3 water molecules, and in the second case, the "tetra" means there are 4 water molecules.

If you are making an aqueous solution of this material, it will make no difference in its properties (if not, it is possible it could matter that there is extra waters, I'm not sure about that). One thing that certainly does change is the molecular weight -- make sure to calculate the molecular weight properly including the right number of waters.