These freeze dryer trays fit perfectly in the Medium Blue Alpine freeze dryer. Being stainless steel (304 SS), they are incredibly durable, long-lasting, and warp-resistant. Since these freeze dryer trays are standard-sized, replacements can be found online or in person at any retail store selling baking supplies. We suggest using silicone mats with these metal trays to prevent food from sticking. Less cleaning, more freeze drying! Stainless steel is incredibly durable. It can withstand high and low temperatures and should last for years with proper use and care. That's why stainless steel is the go-to option for freeze dryer trays.