It has high elasticity with 2 to 3 phr. of combined sulfur content. Hardness shall be
varied according to kind and weight of ingredients, however, shall be in the range
of 30 to 80 with JIS* 
(or Shore A) durometer. It has good resistance to corrosion and abrasion and is free
from cracks by shock with service temperature of below 70°C.
*Japanese Industrial Standard