Save the hassle and frustration of trying to drill holes in mason jar lids for mushroom growing (mycology).
Our lids have the holes stamped in them for clean edges. Pre-installed .2 micron filter patch and rubber injection port.
Pack of 10 prepared lids.
While many of our products have free shipping, the shipping costs for heavier items are calculated by weight and distance. Please consider the labor and resources required for shipping and understand that we cannot provide free shipping on some items. We offer a local pickup option at our warehouse in Northern California near Sacramento.