Current generation SRAM and Quarq power meters and cranksets use an 8-bolt mounting interface to secure the spider onto to drive-side crank arm. The SRAM Torx T20 Spider Bolt Kit is pictured below:
T20 Bolts Included
SRAM and Quarq 8-bolt power meters as well as SRAM 8-bolt chainrings come with T20 bolts. In addition, the Quarq DZero DUB Crank Arms and the SRAM XX1 Eagle DUB Crank Arms also include them.
T20 Bolts Not Included
SRAM Force D2 Crank Arms and SRAM Red E1 Crank Arms do not include bolts.