Bessa III/Fuji bellows material?

[archeophoto]

Sorry if this has been addressed before, but I can't find any info about this.
What material is the Bessa/Fuji III's bellows made out of? Is it leather or vinyl or something else? I know this might be hard to tell, but does it feel to be a durable material?

Thanks!

 

[Jamie123]

I don't have my Bessa III anymore so I can't check but if I remember correctly the bellows has two layers. Inside it's some sort of tough fabric and outside it seemed to be some sort of thin vinyl.
Anyways, to me it feelt reasonably durable and not too fragile but it's still a bellows so it serves to be prudent. It'll take a gentle poke or two and pop back out but I wouldn't test it too hard.