Every laser comes with a calibration card telling you the wavelength (every laser is a little different - usually 650 to 660nm). Every laser runs on normal USB power (5v) which comes from phone chargers, USB cigarette adapters, USB batteries, computers, laptops, etc. Comes with 1 meter long power cord. You must supply your own USB power source.

This laser has 2 advantages over the cheaper laser I sell: larger beam and glass lens.

The glass lens means it is easy to clean without scratching. The other laser I sell has a plastic lens secured with a spring and the spring scratches the lens more and more every time you take it apart. This laser doesn't have any spring touching the lens.

See diagram in product images before reading on.

The beam diameter is 2.6mm which is quite large for lasers (my cheaper laser has 1.75mm diameter beam). This means you can test smaller focal length mirrors. The mirror coverage depends on your diverger.  Formula is:

F/# mirror coverage = lens F.L. / 2 / laser_diameter

minimum recommended column has 50% extra coverage