What's the best gift for a 14-15 years old boy?

So.. I'm meeting my nephew for the first time ( from my half brother) and it happened that he graduated from middle school so I thought of giving him a congratulation gift but I know nothing about him and his hobbies or if he already have that thing that I will give him or not... So any suggestions?

What's the best gift for a 14-15 years old boy?
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