SPECS: Bases - Aluminum, anodized finish, matte black. Steel hardware. Front Screws - Includes (1) of each size: 3-56 tpi, 3mm x 0.05, 3mm x 0.06, 5-40 tpi, and 6-48 tpi. Front Sight: Base - 11⁄16” (2.7cm) long x 5⁄16” (7.6mm) wide. Center Rod - Red polymer, ¾” (1.9cm) long x .05” (1.3mm) dia. Outer Ring Rod - Green or yellow polymer, ¾” long x .08” (2mm) dia. Rear Sight: Base - 1½” (2.7cm) long x 5⁄16” (7.6mm) wide. Rod: Red polymer, 5⁄8” (1.6cm) long x .05” dia. Fits rib widths: .24” (6mm), .25” (6.35mm), .29” (7.5mm), .313” (7.95mm), .315” (8mm), and .39” (10mm).