Avantor supplies retort rings for the support of funnels, flasks, test tubes, and burettes in retort stands. Open rings allow easy removal of sample containers and feature PVC-coated aluminum construction to prevent scratching of glassware. Cast iron and wire rings with optional clamps are also available. Long extension arms provide easy connections to frames and stands and are sold in a variety of lengths and ring diameters. Holders to mount rings to stands and frames are also supplied at Avantor.