Sigma TS-31 Tripod Collar - for 120-400mm, 150-500mm and 50-500mm f4.5-6.3 Lenses Sigma TS-31 Tripod Collar - Sigma 1 Year North and South America Limited Warranty (3 Year USA Extended Warranty for a Total of 4 Years from Date of Purchase) Sigma TS-31 Tripod Collar - for 120-400mm, 150-500mm and 50-500mm f4.5-6.3 Lenses