High Quality Silicon material,applicable power up to 60W-400W ,The silicon reflector lens has good optical thermal properties, dissipates heat quickly and is suitable for high power laser-tubes. Silicon reflective lens with 5 layers of gold plating, reflecting up to 99.8%, reducing light loss due to reflection Normally,A laser-machine needs 1 lens 3 reflective lenses Laser-lenses with lengths of 24.4 mm, 38.1 mm and 50.8 mm are suitable for engraving. If used for cutting, we recommend working with laser-lenses with a length of 63.5/76.2/101.6/127mm. color:Silver Material:silicon size:Diameter 20mm, Thickness 3mm Package Contents: 3 x laser-pointer lens Only the above package content, other are not included. Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.