300ml glass jars with single butyl  rubber injection port secured into the lid. 
Ideal for making water spore jars, agar jars or liquid culture jars.
Simply fill with your your choice of liquid and pressure cook until sterile. Screw the lid on loosely to prevent broken jars while pressure cooking. When sterile and while the jars are still hot from the pressure cooker. Screw the lid tight and use when needed.
Rye grain water makes a great liquid culture base. For this simply boil up a hand full of grain for each jar. Sieve out the grain and use the water. Add 180ml of water and leave 120ml empty air space. 
Honey can also be used at 5% concentration. 
Pressure cook both rye and honey jars for at least 2hrs at 15ps