I recently purchased the 3.5W Laser integrated with the DIY Engraver from Endurance, to replace a slow 200mW Toy from China. After 100+ Engravings, i can say that overall Engraving Time on Wood improved up to 10 Times, compared to my old Laser. Quality of the Engravings is very good, assuming proper focusing of the Laser Beam. I did not try to engrave Stone yet, but i am pretty sure it will work, but i plan to buy a more powerful Module/Engraver from Endurance later on, for advanced Purposes.