CRS Pure-Pass Sealing Mats protect wells from leaks, contamination, and evaporation during sampling and storage. Pure-Pass Sealing Mats are available in clean room molded EVA mats or silicone mats that undergo additional processes to reduce extractables. A superior re-seal reduces sample loss from evaporation. For 96 and 384 in round and square wells. Each mat has an alphanumeric grid reference and is suitable for long term storage.