The SMI (Smart Micro Inert) union kit includes double ended 0.5mm ID ferrules for connecting capillary columns of 0.53mm ID (670-680um OD.) SMI inert connectors feature low heat capacity, low dead volume, and no leakage when properly installed. Includes 1 union body, 5 ferrules, and installation tools. For the replacement union body, use 227-35026-03 (5/pk) For replacement ferrules use 227-35025-06 (10/pk)