Gift ideas for an 11 year old starting to get into bouldering

Hello everyone,

My 11 year old stepson's birthday is coming up soon and I want to get him a gift he will appreciate to help us develop a bond. He's recently become very interested in bouldering (indoors), so I thought about giving him something that supports his hobby and helps him get better at it. I'm not into bouldering myself (I tried, but I'm too afraid of falling!), so I want to ask someone more experienced for guidance. A book perhaps or some gear? He already has a chalk bag, but that's it. Suggestions are very very appreciated. Thank you in advance! =)