The TruGard X1 flip-up welding goggles feature premium grade 50 mm lens offering maximum eye protection during extreme jobs like welding, torching, brazing etc.  Soft PVC opaque green frame with ABS material. The lens has 3 layers, the inner and out layers are 1.0 x 50mm PC transparent and the middle layer is 2.0 x 50 mm green lens with 6 air breathing vents.