Alternatively, IVC filters can be placed at the bedside either using fluoroscopy or transabdominal or intravascular ultrasound. Knowledge of the normal and variant anatomy of the vena cava is important for successful placement of vena cava filters and prevention of complications.
Welder's Glass. Welder's Shade Glass. A heat resistant grey-green tinted glass made to provide the correct eye protection for every welding operation. The shade numbers 1-14 refer to the density needed for the different welding operations. The higher the number, the darker the shade. Stock sheet size is 0.108 thick in Density 3 through Density 14.
That's why you want different shades. There's a problem that welders get on occasion. It's called flash burn to the retina. That's what happens when your helmet is not dark enough, or if you forget to put your helmet down (been there); or somebody's welding across the shop and you just happen to glance at that arc.