IBM ThinkPad A20m Hardware Maintenance Manual page 26

Laser compliance statement
Opening the CD-ROM drive, DVD-ROM drive or the other
optical storage device could result in exposure to
hazardous laser radiation. There are no serviceable parts
inside those drives. Do not open.
Some CD-ROM drives, DVD-ROM drives or the other
optical storage devices contain an embedded Class 3A or
Class 3B laser diode. Note the following:
20
ThinkPad A20m/p, A21m/p, A22m/p