H40W/H20 usually only has two issues.
1) A defective pressure switch (most common)
This can be identified by asking the buyer to test the light with both pressure switch and the regular tail cap switch. If one of them work, the other is defective.
2) A defective LED module
LED module is a drop in and can be easily replaced if the buyer is comfortable with it.
The inventory item is ACC-LEDDROPIN-ORION-H40W
The instruction sheet about replacement can be found at /Customer Service/Images/Troubleshooting Images/H40W H20 dropin/
A) Test the LED dropin in a light before sending it out
B) Include the instruction with the package
C) Pack the LED in a (battery) Box before packing in the envelope to protect it.
