HandleBar end knob - what size or allen wrench is needed?

[Running Reddog]

I have just recently purchased a 2025 Spyder F3 Limited SS. I would like to change the handle-bar end nuts.
What size or type of wrench do I need to remove the end caps? I have tried both metric and standard wrenches,
and none will work. Only one, nearly fits, but it spins around. The wrench inserts slightly. Thanks

 

[Jetfixer]

It's a 10mm Allen....