This is 100% natural rubber elastic. 

it is sold IN 5 YARD PACKS

Rubber elastic is the best elastic for swimwear. It holds up the best in terms of tension, plus it’s resistant to chlorine, salt water, UV, and sun tan oils.
Rubber elastic has other uses beyond swimwear as well. It can be used for sportswear, underwear, shoes, seat covers, and more. 
we offer it here in  1/4” and 3/8” widths.