Product instructions: 
1) Automatically changes from light state to dark state when an arc is struck 
2) The shade number can be set manually between DIN9 DIN13 
3) At the moment of stopping welding, the filter screen automatically changes from dark to light state slowly so as to protect eyes from being hurt by the rest arc  
4) The ultra high performance of UV/IR auto-darkening filters provide full protection for the user's eyes 
5) Protective plate which is free from stained chipping protests the filter screen from being damaged by sparks and particles 
6) You can enjoy the simple operation by pushing only one button to select the shade number 
7) Total weight: 420 grams 

GY-A features:  
1) Viewing area: 92 x 42mm, 98 x 40mm 
2) Size of cartridge: 110 x 90 x 9mm 
3) Light state: DIN4 
4) Darken state: DIN9-13
5) Switching time: <0.0001s
6) Rate of UV: 313N.m<0.002%, 365N.m<0.0002% 
7) Rate of IR: 780-1,300N.m<0.0002%, 1,300-2,000N.m<0.002% 
8) Operating temperature: -5-+55°C  
9) Storing temperature: -20-+70°C 

GY-B (with sensitivity knob) features: 
1) Viewing area: 92 x 42mm, 98 x 40mm 
2) Size of cartridge: 110 x 90 x 9mm 
3) Light state: DIN4
4) Darken state: DIN9-13
5) Switching time: <0.0001s
6) Rate of UV: 313N.m<0.002%, 365N.m<0.0002% 
7) Rate of IR: 780-1,300N.m<0.0002%, 1,300-2,000N.m<0.002%
8) Operating temperature: -5-+55°C 
9) Storing temperature: -20-+70°C 

GY-C features:   
1) Viewing area: 98 x 50mm 
2) Size of cartridge: 110 x 90 x 9mm 
3) Light state: DIN4
4) Darken state: DIN9-13
5) Switching time: <0.0001s
6) Rate of UV: 313N.m<0.002%, 365N.m<0.0002% 
7) Rate of IR: 780-1,300N.m<0.0002%, 1,300-2,000N.m<0.002% 
8) Operating temperature: -5-+55°C 
9) Storing temperature: -20-+70°C