*Medium Includes 5 stainless steel trays for use in a medium freeze dryer (can order--comes within 3-5 business days).
*Large Includes 6 stainless steel trays for use in a large freeze dryer (have one in stock).
It's very nice to have an extra set, in the freezer all ready to go the minute your current batch comes out--no wasted time & more space is always helpful when you have a lot of whatever you're freeze-drying!
