Sorry about that!! As far as I know, these two collars are essentially the same. The Sheene is a more fitted style than the 1930s Half Belt, since it is the Cafe' Racer fit (very trim through the torso/waist area). The 1930s Half Belt can be adjusted to look trimmer (with the side cinches), but it is a somewhat looser fit than the Cafe' Racer.
How much difference in fit is there between the regular 30's HalfBelt and the slim fit 30's HalfBelt? I would like to get a collared Brown FQHH jacket am debating between the slim fit HalfBelt and the Sheene.
Thanks.