The grey septa, also know as sticky nickels, are used to seal the needle puncture area when performing modified atmosphere packaging (MAP) testing. Use of a septum prevents air from entering the inside of the package while testing. It helps to ensure an accurate sample of MAP gas.
The grey septa have a standard duty pressure sensitive adhesive seal.
The part number is 001016. Available in 100 x 10 sheet packages or in bulk as a 3425 piece reel.