These 300mmm long PYREX® hybridization tubes have a 35mm inner diameter (I.D.) and are designed for use in hybridization chambers. They come with Corning® standard GL 45 orange plug-seal caps (No. 1395-45LTC). A silicone O-ring (No. 1395-OR) is used to ensure a leak-resistant seal. An optional Corning vented membrane cap (No. 1395-45LTMC) is available for low temperature assays.