Sanyo jj-p4 the smallest cassette authentic Walkman

Product Name: Sanyo jj-p4 the smallest cassette authentic Walkman
This is a collectible item (rare, unique design, and vintage), not like any normal slim version, this is literally the smallest Walkman ever built, smaller than a cassette case, also smaller than hitachi cp-88r and Sony wm-701c or wm-10 measured by volume. Full metal inside out, only a very small scratch(Last picture) but can be covered easily . Function wise, it's working with a low quality belt, even so the sound is pretty good from on side, when reverse to the other side, it play the same track backward, but sometime it play correctly, so it's either some contact issue or the belt ? Powered by either gumstick battery or AA battery with battery case Overall authentic very good condition. What's included: player body and battery compartment(battery, cassette not included) What's not working: they auto reverse has one side playing backward but sometime it works just fine, maybe contact issue, can't figure it out.