There are different material that can be uses for spectacles lens.

The most common and good performance material in safety spectacle is Polycarbonate (PC)

PC material is known as impact resistant, UV protection, clear color, light weight and economic price.  


Ultra violation radiation is divided into UVA (320~400nm), UVB)290-320nm) and UVC (100~290nm).

UVC are completely block by our ozone layer.  

UVA and UVB can cross the ozone layer that can cause burn to our skin and eyes with extended exposure.

Just like the use of sunscreen to prevent burn on skin, the use of safety spectacles with UV protection are important to prevent burn to the eyes.  Parkson Safety offer safety spectacles with UV380 treatment that can block 97% of harmful UV Rays.   UV400 treatment are available to block 99.9% of harmful UV rays.

Test report are available upon request to demonstrate Parkson Safety products with UV protection

According to ANSI Z87.1 regulation, there are 2 differnt impact test and 3 different electrical insulation test:
--Impact test:
Type I: impact test for falling power from top, this is usually for safety industrial helmet
Type II: impact test for the falling power from top, right and left side. This is usually for motocycle helmet.
--Electronic test: 
Class E: test with 20,000 voltage
Class G: test with 2,200 voltage
Class C: not necessary to go for electronic test. 

If such situation happened, please check welding helmet by following procedure step by step:
Press "TEST" button located on filter lens,
- Filter changes from a clear state to a dark state immediately after pressing "TEST" button, and then changes back to be a clear state. That means battery is working. Please adjust "SENSITIVITY" knob to "high".
- "Low Battery" light flashing for a second; or filter doesn't change to dark status after pressing "TEST" button, it may "low battery". Please change the battery immediately.

Generally speaking, lens shade depends on current amperages, you may download attached welding lens chart for reference. 
Here simply list as below:
Covered electrodes: please chose shade#9--#14,
MIG: please chose shade #10-#15
TIG: please chose shade#9-#14
MAG: please chose shade#10-#15