Mike -
It's a curing Agent - here's the short version of curing agents:
Prague powder #1 is a mixture of 1 part sodium nitrite and 16 parts salt. You normally use 1 level teaspoon of cure for 5 lb. of meat. Used at any time meat is not immediately put into freezer or refrigerator, Such as smoking, air drying, dehumidifying, etc. This is similar to and sometimes called Curing Salt.
Prague powder #2 is a mixture of 1 part sodium nitrite,.64 parts sodium nitrate and 16 parts salt. You normally use 1 level teaspoon of cure for 5 lb. of meat. mainly used for products that will be air cured for long time like: Country Ham, salami, peperoni, and other dry sausages.
Instacure 1 is a mixture of 1oz of Sodium Nitrite (6.25 %) to 1 lb of salt. Used at any time meat is not immediately put into freezer or refrigerator, Such as smoking, air drying, dehumidifying, etc.
Instacure 2 is a mixture of 1 oz of Sodium Nitrite (6.25 %) along with .64 oz od Sodium Nitrate (4 %) to 1 lb of salt. mainly used for products that will be air cured for long time like: Country Ham, salami, peperoni, and other dry sausages.
Note: The Curing Salts above contain FDA approved red coloring agent that gives them a slight pink color thus eliminating any possible confusion with common salt
Morton's Tender Quick is a mixture of salt, sodium nitrite, sodium nitrate and sugar. You normally use 1 level tablespoon of cure for 1 lb. of meat.
Saltpeter is potassium nitrate and is also used as a curing agent but I know n
You may be able to get some from your local butcher but most us us order them online from sausage supply places.