Manufacturer. Features (1). Certified by GC/MS to be contaminate free for VOC Analysis (2). Magnetic screw caps -8 mm centre hole (3). Screw headspace caps, septa, and vials are designed especially for use with Aijiren's and CTC rotating or robotic arm samplers. (4). Round bottom headspace vials (5). Septa are blue (PTFE) sample side; white