battery well dimensions for ecosmart metro razor scooter

hi i need help iam trying to upgrade my razor ecosmart metro to lithium and i want this company to buiild me a 18650 battery pack but i dont know how to get the measurement in the space were i can put the new packm if anyone knows the dimensions the length width and height for that space were the sealed lead acid batteries occupy i really would appreciate it i need those measurements so they can build my pack that way i will know how much amp hours i can squeeze in the area thank you guys very much for your help