Hey everyone

I'm new to mechs and have a couple of questions. (I can hear you groaning

)
I'm looking at this for my boyfriend.
Sigelei #24 with Locking D Ring
I saw a couple of comments about a button problem.. does that apply to this?
Do i need to buy any special springs, screwdrivers or doo-dads for it to work?
I don't see a battery or charger in the photo.. so i guess it's safe to assume those are sold separately?
Do we need an adapter for an evod to screw onto this?
In short: is it safe? What else do i need to buy?
I really appreciate any help anyone can give me