Typical size: The picture showing ferrocerium toggle with 5/16" x 1" with 2 lanyard holes drilled at 5/32" apart centered. 

5/16" Diameter x 1" Length ( 5/16" x 1" ) or 8mm Diameter x 25.4mm Length 
Reference weight : 0.28 oz/pc or 8 gram/rod approximately 

Ferrocerium toggle fire starter is made from Iron(or Ferro), Magnesium and mostly of an alloy of rare earth metals (or rare earth elements) called mischmetal with an excellent pyrophoric percentage :  98%min. 
The required chemical composition:   
Mischmetal              76%MIN.
Fe (Ferro or Iron)     18 ~ 21%
Mg ( Magnesium )    1.5 ~ 2.5%
Hardness :               90 ~ 170 HB
Surface   : black lacquer coated.
Size available :   5/16" up to 1/2" Diameter  x  1" up to 2" Length.

Application : It is widely equipped with para cord survival bracelets, survival buckles and paracord belts, etc., as the toggle fire starter in scouting and camping, 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. 

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