The OCTO-8 set is designed for the HU100 Laser key system with 8 cuts. This system is very popular on Chevy's, Buicks, Cadillac and GMC vehicles. This system has door and ignition spaces 1 to 8.
OCTO-8 set has 128 keys. Try both sides.
16 Rings with 8 keys on a ring all numbered.
Simply try each key in the lock that you are working on and turn left and right. Try both sides of the key. Once you find a key that turns you simply look it up on the key chart for the shallowest cuts and adjust, or by using the OCTO-8 key in the ignition you can turn the ignition to the correct position to depress the retainer and remove to see the key code!
THERE IS A LIMITED SUPPLY of OCTO-8 sets.