Tech Sight's SU16A1-EL Adjustable Aperture Sight for the Keltec&reg; SU16 series, SU22, PLR16 & PLR22 rifles and pistols. Rear sight elevation version. Rugged All Steel Construction. Rear sight Windage & Elevation adjustments w/ incremental spring loaded detent locking. .062 diameter aperture. Low profile using minimal rail space. .062 diameter aperture. Additional aperture inserts available. Easy installation - clamps on picatinny rail.