Spot rubber flared up mainly on covering purchases at lower levels on Wednesday. RSS 4 firmed up further to ₹136 (131) a kg, according to traders. The grade improved to ₹134 (131) and ₹131 (128) respectively, according to Rubber Board and dealers. December futures improved to ₹138.10 (133.32), January to ₹143.39 (137.88), February to ₹146.13 (140.51) on the National Multi Commodity Exchange. RSS 3 (spot) firmed up to ₹155.14 (151.66) a kg at Bangkok. December futures increased to ¥282.3 (₹165.64) a kg on the Tokyo Commodity Exchange. Spot rubber (₹/kg): RSS-4: 136(131); RSS-5: 130 (126); Ungraded: 122 (120); ISNR 20: 122(120) and Latex (60% drc): 83 (82.50).