The Prep Bible.Shield SMS Mini Sight
No longer available
Both of these are Shield Sights red dot optics built for handguns, using a 4 MOA red dot reticle with 1x magnification. They share a lightweight, waterproof, non-magnified, illuminated design, so the choice comes down to lens construction and extra features rather than the basic dot presentation.
The SMS-4MOA-POLY is the lower priced option at $169.99, with a straightforward feature set of illuminated, waterproof, lightweight, and non-magnified. The SMSc-4MOA-GLASS costs more at $259.99 and adds a glass lens along with parallax free operation and a lens cover, on top of the same illuminated, waterproof, and lightweight qualities.