When selecting laser safety glasses for low power alignment lasers, there is a precise balance between providing enough protection and while still allowing visibility of the beam.
For green ( 532nm ) and ( 635nm, 650nm) red lasers to be classed as eyesafe they are required to be less than 1mW of power. In regular indoor lighting conditions around 0.2mW of green (in a spot a few millimeters in diameter) is visible over several meters and for red lasers around 0.5mW. Over shorter distances they can still be visible with lower power, however in direct sunlight more power is needed to maintain visibility.
Taking this into account if you have a 25mW green 532nm laser and want to cut it down to an eyesafe level then laser safety glasses that cut down 532nm by around 30X ( OD of around 1.4 / 1.5 ) would be ideal and the same goes for a 25mW red laser.
The LG-007 red and green laser safety glasses cut down both wavelengths by around 30X so are ideal for lasers up to around 30mW. More information can be found via the below link.
As there are many factors to be considered don't hesitate to contact us on firstname.lastname@example.org to discuss your requirements with one of our laser safety experts.