MicroSolv™ Brand Caps - Crimp Caps with Sil/PTFE septa and natural rubber for 8 & 11mm vials. Open Hole - Silver aluminum crimp caps without septa. Septa - Low Bleed (siloxanes are eliminated), Non-Slit, Pre-Slit, PTFE only for single injections (will not reseal), PTFE-Silicone Rubber-PTFE (red/white/red), White Silicone Rubber with Red PTFE.