The MAX-9 Standard Slide Assembly (#90744) and Standard Slide Assembly with ReadyDot(TM) Optic (#90745) allow installation of micro red dot optics on MAX-9 pistols equipped with a loaded chamber indicator (model 3518). These accessories replace the pistol's slide with an optics-ready, direct mount slide for co-witnessed JPoint and Shield-pattern micro red dot sights. The #90745 Slide Assembly comes equipped with a ReadyDot micro reflex light-gathering fiber optic red dot sight already installed. Both SKUs come turnkey with all sights, barrel, extractor and other slide components to simplify installation using the included installation instructions. Mfg: Ruger