The wider bracelet is made from CPVC which means it has a low density core with two surfaces. The core is more porous and you can see it absorbs the dye creating a more saturated color.
The thinner bracelet is solid PVC so the dye penetration is generally less resulting in a lighter color.
Some other designs you might like:
thin oval bangles stained PVC 4058
small stack of plastic faux bone bangle bracelets with dyed color 4057
large bone bangle bracelet 4028
thick bone bracelet PVC cuff bracelet contemporary primitive design 3752
This and other pvc bracelets can be found on ArtiFactSite your source for traditional forms rendered in modern materials.
design and photographs copyright 2016