The CS4-4 out of a Vans bag is shown hanging on a magnet.
I removed the mandrel which appears to be steel but the body is aluminum.
AACQ4 from Vans below that both the mandrel and body are not magnetic
the CS4 weighs about 1 gram. The AACQ4 about 1/2 a gram.
AACQ4-4 is aluminum body and stem
It has a much lower setting force/tension which is why they are used when riveting through the canopy (when set with a hand tool the difference is quite noticeable).
CS4 vs AAPQ44:
Maximum Grip, Diameter, and Countersink Angle: Same ( 0.250", 0.125", 120 deg)
Minimum Grip: 0.063" vs 0.126" (CS4 can grip 0.062" thinner)
Shear Strength: 155 lb vs 225 lb (AACQ is 70 lb or 45% stronger)
Tensile Strength: 205 lb vs 250 lb (AACQ is 45 lb or 22% stronger)
Summary:
The AACQ has an aluminum mandrel instead of steel, but it is a locking mandrel which actually results in a stronger rivet.
The CS4 is a multi-grip rivet, allowing it to be used in a wider range of grips than the AAPQ rivet.