Thank you all for the replies!
Batteries : To be honest I don't know which one is better (pretty ironic considering I'm an electrician right

). Rechargeable is preferred
Size: Small enough to fit in a cargo pocket
Bright/run time: Something in the middle, really bright for a decent time
I don't need to light up a room a smaller focused beam is just fine
I will take a custom or store bought.
CRI doesn't matter tbh.
Thank you!