IBM X4 manual Danger

DANGER

Do not open the optical storage drive unit; no user adjustments or serviceable parts are inside.

Use of controls, adjustments, or the performance of procedures other than those specified might result in hazardous radiation exposure.

Class 1 laser products are not considered hazardous. The design of the laser system and the optical storage drive ensures that there is no exposure to laser radiation above a Class 1 level during normal operation, user maintenance, or servicing.

Some drives contain an embedded Class 3A laser diode. Note this warning:

DANGER

Emits visible and invisible laser radiation when open. Avoid direct eye exposure. Do not stare into the beam or view it directly with optical instruments.

x ThinkPad® X4 Dock User’s Guide