Is a red laser pointer dangerous for cats?

Check the label. If it is marked "Class II", "Class IIIa", "Class 2" or "Class 3R", it is safe. All of those have power less than 5 milliwatts. The "Class II/Class 2" pointers are the safest--they are limited to 1 milliwatt. Do not use blue or green laser pointers as toys, even if they are rated Class 3R.