I'm not particualy knowledgible about this,so i might get my A$$ handed to me so please bear with me.I know what you can buy a repo. for,but this is an original.I guess this requires some sort of batt. pack,so I did not try to test it,like I would an early Chevelle/Camaro one.The needle lies on zero like it should,and bounces easily when unit is touched.It has been inside my buddies house for 40 plus years,finally talked him out of it.The price is not firm,just have to start some where.More pics upon request