Shop › Lee 4-20 Furnace Lid Image 1 of 1 Lee 4-20 Furnace Lid $17.95 Decreases heat up timeGreat spot for preheating your molds and ingotsCNC Machined from 6061 AluminumLooks great. Get notified by email when this product is in stock. Quantity: Add To Cart Added! Decreases heat up timeGreat spot for preheating your molds and ingotsCNC Machined from 6061 AluminumLooks great.