Four interchangeable high-intensity LitePipes are included with all M-Series sights allowing the shooter to adjust to existing light conditions. The S-Series includes a single LitePipe in your choice of green or red at a more economical price.HiViz?s snap on/off magnetic base is available in four different sizes to fit virtually any rib width from 11/64" to 9/16". Refer to the selection chart for compatibility. Not compatible with fiber or aluminum ribs.M200 - Fit: ribs from .171" - .265" (11/64 - 17/64"; 4.2 mm - 6.7 mm). Fits Beretta: 686 & 687 models with ultra narrow rib AL390 A304 AL390 Field 391 Urika Field; Browning: Gold Series 28 ga. and .410 Citori; Sigarms: SA-3 Hunter SA-5 Upland; Benelli: 20 ga.