GST classification for synthetic rubber applies at prescribed rate until the notified expiry of the concession. Goods classified under heading 4002-synthetic rubber and factice derived from oils in primary forms or in plates, sheets or strip, including mixtures with heading 4001 products such as latex, styrene-butadiene rubber, butadiene rubber, butyl rubber and EPDM-are placed in Schedule 3 and attract GST at the prescribed rate of 18% for the notified period up to the stated expiry.