Your qualifiers need to have "pi" in the title. "pi" can be part of a word; ie picnic, pine, pilot, pirate, rockpile, spirit, Capitan, hospital, spit, epitaph etc.
The cache is a bison tube in a larger host. You will need a pencil.
You may not use the same word more than once. The difficulty rating is for finding the qualifiers. Physically, the cache is a 1 as it is visible from the back side.