3-Star (TM) Bulbing Type Blind Rivets. 

Aluminum Rivet Body / Aluminum Mandrel

Shear Strength: 5/32 Dia. 112 lbs; 3/16 Dia. – 202 lbs.
Tensile Strength: 5/32 – 225 lbs; 3/16 Dia. – 247 lbs.