I'm in the US and I use Envigro blocks (previously known as Harlan Teklad 201
. It can be ordered online from Amazon and other websites. I'm on a hamster FB group and was told that The Power of 5 Food has 23% protein, which is good for younger hamsters (under 6 months of age), but as hamsters age, they should have less protein. The Harlan blocks I use have 18% protein. Many people use Mazuri because it is easily available in pet stores. Many people have stopped using Oxbow for the reasons mentioned above.