This type of iron nails is made of cold drawn high quality carbon steel materials, heavy galvanized. Smooth shank, no head.
Common specification of concrete nails with no head:
Nail diameter 1．6 mm x Length 20mm
Nail diameter 1．6 x Length 25mm
Nail diameter 1．7 x Length 30mm
Nail diameter 2. 0 x Length 40mm
Nail diameter 2．0 x Length 50mm.