The best for this price!
I highly recommend this beam expander I have used it on several lasers including the blue 1.5 Watt 3 Watt and 5 watt laser and green laser 1 watt. I have actually measured the the diode shape Beam at various distances and it is 1/2 size measured the long dimension another words it should double the energy over not having this beam expander the vertical Dimension is pretty much the same. The actual diode image at distance being a rectangular shape box typical of blue lasers diodes . Visibility should be comparably enhanced. The lenses only reduce the output by approximately 10% so the energy out of the laser is 90% with this being attached. These measurements being done with a laser power meter with and without the beam expander on it and at the same temperature and same battery charge.
This is by no means a technical review, as I do not have the technical specifications for the optics. This is another excellent product from Sanwu, the Beam Expander gives you fine control of your laser over varying distances. I particularly recommend this product for use with 635nm high power lasers, as it goes a long way to effectively reduce the bar shaped beam profile of these diodes. For other wavelengths it gives great performance with increasing the visible range of your laser and reducing divergence over a distance. I highly recommend this bit of optics for your laser. 10/10!