Too much or too little resistance to the needle can damage the septum, damage the re-sealing, the needle may be clogged by the core ring of the septum material, or the autosampler may be damaged. The Used Aijiren silicone rubber/PTFE septum is designed to give moderate resistance to the autosampler needle during the injection process, so it penetrates correctly into the vial without damaging the septum or injection needle.