BIS 43X/48 (Backup Iron Sight, 43X/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 their OPF-G43X/43, RMRcc on GLOCK's G43X and G48.

BIS, 43X/48 is slightly different from GL-527 on which it's based.  These FCD particular changes are:

• Tritium 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.

Designed and made in the USA. Special thanks to the professionals at Ameriglo that made this project possible, they're grateful for their willingness to work with a small outfit like them for their shared customers / users.  GLOCK's G43X/48 with RMRcc is approved by many agencies, most of which require red dot pistols be equipped with metallic, co-witnessing backup sights for both on and off duty use. BIS, G43X/48 was created with them in mind.  

Please NOTE:

• BIS, 43X/48 is compatible with OPF-G, DPP (Delta Point Pro) as well, the sights are very low in DPP's window.  For DPP, they recommend Ameriglo's GL-808 with 0.5" front sight height.
• If you don't have a sight pusher or the equipment to install rear sights, please bring it to a qualified and competent gunsmith to perform the installation.  It's not uncommon to have to fit the rear sight to the dovetail, a competent gunsmith should be well familiar with the reason and method.  They've seen more than enough expensive muzzle devices ruined by "gunsmiths" that used a screw driver to install them instead of a torque wrench, and hand tightened optics plate screws when a torque value is clearly noted in multiple places.  
• Rather than being loose (easy to install), we prefer the sights be tight, so it won't be knocked off zero easily.  Tolerances of the dovetail and sights also come into play, which results in some being easier, while others are harder to install.  A qualified gunsmith can deal with these easily.