BIS, G43X/48 (Backup Iron Sight, G43X/G48) is a collaboration between Ameriglo and FCD. Specifically made for Glock®G43X and G48, these sights are based on the superb Ameriglo GL-527 with a front sight height of 0.450", and a rear sight height of 0.554", this sight sets provide lower 1/3 co-witness with the Trijicon RMRcc when used with the OPF-G43X/43, RMRcc on G43X and G48.

BIS, G43X/48 consists of the following:

• Front sight, available with either green Tritium and white outline (no serrations), or serrated front sight, no tritium or white outline.
• Rear sight, serrated.

BIS, G43X/48 is slightly different from GL-527 on which it's based. These FCD particular changes are:

• Tritium option for the front sight.
• Front sight back strap angle is steeper (25 degrees on the serrated, non-tritium front sight, 20 degrees on non-serrated, tritium front sight) to mitigate snagging when the pistol is drawn from and out of the holster where it's likely to encounter clothing, and the front sight's top corners are softened.
• Rear sight is horizontally serrated.