With some scotch tape for a diffuser—a diffuser is definitely needed.
The 9 x 5mm light with White Leds draws 260mA, or 29mA each, when using 3 AAA (4.5V). The Vf for the 670nm Reds(AlGaAs) is much lower, 1.8V @ 20mA, and the radiant power is 6mW each at that current. The max continuous current is listed as 50mA.
The radiant power of 40mW/cm2 at the exit of the FL may have come from a total radiant of ~150mW with 450mA current draw from the 3 AAA cells, using 3.8 cm2 area of the 2.2cm diameter lens.
example of Vf change by color:
