Round Cobra Chains RCOB-40 (0.8 mm – 2.1 Gr./Ft.) RCOB-50 (1.0 mm – 3.2 Gr./Ft.) RCOB-65 (1.3 mm – 4.0 Gr./Ft) RCOB-100 (2.2 mm – 9.8 Gr./Ft)