[Harp-L] Bill Barrett

[Rick Dempster]

I've only just become aware of Bill Barrett, and I like what I hear.
Does anyone have any idea what he is playing here in this Hohner promo? He
plays at 2.10 and 6.50.
Unless I'm completely tone deaf, that's no standard C chrom. I cannot work
out how he is getting those double-stopp harmonies. I
Is it a standard-tuned chrom? and if so, what key and position is he in.
https://www.youtube.com/watch?v=Lm_e2BZMbJM&t=413s