Ø 1.2 mm (gauge 16) L=5-17 mm (3/16" - ~3/4″) They are made of solid brass and are polished. They have nice round shaped flat heads. Head diameter: for 5-7mm long - head 2.0mm (+-0.10mm) | 8-17mm long - head: 2.5mm (+-0.10mm) For characteristics see below.