Stainless steel & Inox. of 190 Kg/cm2 hardness Heat-treated to ideal Rockwell BEFORE the cut (the only "cold machined" spears in the world).
This high velocity spear's diameter is ideal for a single 19mm? Mega or a 21mm? Super Mega rubber band.
The lengths are metric. To convert to U.S., divide by 2.54

The general guideline regarding which length to use with your Picasso speargun is as follows :

The 90 cm Long Spear for a Picasso 60 cm Speargun
The 115 cm Long Spear for a Picasso 75 cm Speargun
The 130 cm Long Spear for a Picasso 82 cm Speargun
The 140 cm Long Spear for a Picasso 90 cm Speargun
The 150 cm Long Spear for a Picasso 100 cm Speargun
The 160 cm Long Spear for a Picasso 110 cm Speargun
The 170 cm Long Spear for a Picasso 120 cm Speargun
The 180 cm Long Spear for a Picasso 130 cm Speargun

Please note that you could always use the next size spear up or down without a problem