Vintage Levi's
Jeans Guide - Red Tabs
The Red Tab device was
created in 1936 as another identifying feature for Levi's Jeans.
It, along with the arcuate
stitching
could be used to identify a pair of Levis.

Era: 1936-1958
Tab contained Large E and was single sided.

Era: 1958-1971
Tab was 2 sided and contained the Big E

Era: 1971-Present
The 'R' tag was a requirement in order to satitsfy
Tag contains little e
requiremnets for registered trademark status.
contrary to what some people
say, it is quite common.