Typical Size :  The picture showing 1/2" x 4" with a hole for future string or chain attachment. 
Ferrocerium rods have a 7/64" to 1/4" hole drilled 3/16" down on one end for future string or chain attachment, the hole diameter is at buyer's option.
8.0mm Diameter x 100mm Length (0.315" x 3.937")
(approx. 31 pcs/kg);
9.0mm Diameter x 80mm Length(0.3543" x 3.1496")
(approx. 31 pcs/kg);
9.05mm Diameter x 80mm Length(0.3563" x 3.1496")
(approx. 31 pcs/kg);
9.525mm Diameter x 50.8mm Length(3/8" x 2")
(approx. 43 pcs/kg);
9.525mm Diameter x 63.50mm Length(3/8" x 2.5")
(approx. 34 pcs/kg);
9.525mm Diameter x 76.20mm Length(3/8" x 3")
(approx. 29 pcs/kg);
9.525mm Diameter x 101.6mm Length(3/8" x 4")
(approx. 21 pcs/kg);
9.525mm Diameter x 102mm Length(3/8" x 4")
(approx. 21 pcs/kg);
9.525mm Diameter x 127mm Length(3/8" x 5")
(approx. 17 pcs/kg);
9.525mm Diameter x 152.4mm Length(3/8" x 6")
(approx. 14 pcs/kg);
10mm Diameter x 100mm Length (0.3937" x 3.937")
(approx. 20 pcs/kg);

11mm Diameter x 80mm Length (0.4331" x 3.1496")
(approx. 20 pcs/kg);
11.90mm Diameter x 80mm Length (15/32" x 3.1496")
(approx. 17 pcs/kg);
12mm Diameter x 127mm Length (0.4724" x 5")
(approx. 10 pcs/kg);
12.7mm Diameter x 63.50mm Length(1/2" x 2.5")
12.7mm Diameter x 76.20mm Length(1/2" x 3")
(approx. 16 pcs/kg);
12.7mm Diameter x 100mm Length(1/2" x 3.937")
(approx. 16 pcs/kg);
12.7mm Diameter x 152.40mm Length(1/2" x 5")
(approx. 8 pcs/kg);
12.7mm Diameter x 304.80mm Length(1/2" x 12")
(theoretical weigth: 0.245 kg/rod);

14mm Diameter x 110mm Length(0.5512" x 4.3307")
(approx. 9 pcs/kg);
16mm Diameterx 100mm Length(0.6299" x 3.1496")
(approx. 7 pcs/kg);
18mm Diameter x 130mm Length(0.7087" x 5.1181")
(approx. 4 pcs/kg);
19.05mm Diameter x 127mm length(3/4" x 5")
(approx. 4 pcs/kg); 
Ferrocerium rod is made from Iron, Magnesium and mostly of an alloy of rare earth metals called mischmetal with an excellent pyrophoric percentage :  98%min.

The required chemical composition:
    Mischmetal(rare earth metal) : abt. 75%
    Iron                                       abt.18.1-19.3%
    Magnesium                                   3-4%
    Rare earth metal distribution :
    Cerium                                   49-51%
    Lanthanum                              26-34%
    Neodymium                             0-10%
    Praseodymium                         4-7%
Pyrophoric percentage :  98%min.
Hardness :        70-90 HV
Dimension :       2.3mm up to 25.4mm Diameter  x  5mm up to 1000mm Length.
Application : It is used as the firestarters or fire starter in scouting and camping, sparking entertainment, clockwork toys, strikers for welding torches, etc., it is the best compact firestarter we can easily use, plus its dependability,made it a favorite of survival experts, hunters, fishermen and campers. It works equally well when wet or dry. Swedish Fire Steel has even found its way into cabins and backyards as a fool-proof way to light stoves and gas-barbecues.

Operation :  You can get a bare rod or ferrocerium blanks and roll some tape on as a handle, that will give you twice as much ferro to work with and may save a little room as well. You simply pull your knife blade or striker slowly and firmly down the length of the ferrocerium rod, and sparks easily ignite a stove, barbecue, paper, dry grass bark, tinder, this iron rod is water resistant, and its 3000° C spark works well even when conditions are wet, cold, and less than optimal. this ferro cerium flint fire starter is a favorite of survival experts, hunters, fishermen, backpackers, campers and boy scouts, etc.,  Also the ferrocerium rod can be inserted into one side of Magnesium block to build a Magnesium Ferrocerium Firestarter, etc.,

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