Warpaper put up their review of the Holosun PARALOW HS403A Red Dot Sight at their website. This Red Dot sight has no external battery housing and it's hidden in the base. This desig allows for  more sleek red dot sight tube. The sight is parallax-free and with a 50,000 hour battery life. The package usually goes with two mounts for a higher profile or lower profile installation.

Read the full review at Warpaper which is made done in English and Chinese.