Silicone 'Self Healing' injection ports for jar lids. These allow for jars of grain spawn to be inocluated with liquid cultures without the use of a flow hood. 
 
Diameter of top disc is 12mm and size of hole in the jar lid should be 6mm. 
 
Can be push fitted, or glued in with a small amount of silicone. 
 
Autoclavable. Set of 12.