Help identifying battery

[jonnybee_123]

Hi I'm trying to identify what battery this is ? It's for a Emu crossbar
I originally thought this was a reenition dorado Chinese battery that is on the new bikes
This model is a bit older and not.sure if the dorado will fit

 

[jonnybee_123]

Can any one help.me source one of these protainium 36 v packs
The "sleeve" it fits in measures 435 mm x 50mm