The Marson 39314 Steel Zinc Plated Thread-sert Kit contains the RN-1 / 39300 Thread-setter tool in a molded plastic case with 10 each of steel inserts 6-32, 8-32, 10-24, 10-32-UNF, 1/4-20 and 6 each of 5/16-18 and 3/8-16 steel inserts. Kit includes all necessary mandrels and nosepieces, wrench and instructions.