Description
The Kriss USA Defiance rear flip-up sight is the factory rear iron that ships on the Kriss Vector and Defiance platforms, so this is the exact part those guns come with rather than a knock-off equivalent. It bolts to any MIL-STD 1913 Picatinny rail and works just as well as a backup behind a red dot on an AR-15 as it does on its home platforms. Folded down it sits at a mere .56 inches (14.22mm) above the rail, which keeps it completely below your line of sight when a primary optic is doing the work.
What Sets the Defiance Rear Sight Apart
Two apertures give you options depending on light and distance. The larger 4.5mm hole is quick to pick up for close, fast work or dim conditions, while the tighter 1.5mm aperture tightens things up for more precise, longer shots. A nice touch here is that the sight folds dead flat no matter which aperture you have selected, so you are never fighting the hinge to stow it.
Windage Dialing on the Defiance Flip-Up
The windage knob is large and textured, so making adjustments with cold or gloved hands is genuinely easy. You get tactile and audible detents both raising and lowering the sight, and adjustments run roughly .75 MOA per click at a 14.5-inch sight radius. No tools are needed to zero for windage once it is mounted.
Mounting the Kriss Defiance Rear Sight
Installation is a one-screw job. Seat it in a Picatinny slot, snug the mounting screw, and torque it to no more than 2 Nm (about 17.7 in-lb) so you do not strip the polymer or crush the rail interface. Built from durable polymer with a matte black finish, it stays light on the gun while holding zero once it is locked down. For anyone running a Vector, Defiance, or a flat-top AR that wants a low, honest backup iron, this is the part the factory trusts.
Key Specifications
- Manufacturer: Kriss USA
- Manufacturer Part Number: DA-PRSBL00
- UPC: 810237027332
- Type: Low Profile Flip-Up Rear Sight
- Material: Polymer
- Color / Finish: Matte Black
- Fits: MIL-STD 1913 Picatinny rail (Kriss Vector, Defiance, AR-15)
- Height Folded: 0.56 in / 14.22mm
- Length Folded: 2.25 in
- Width at Base: 1.19 in
- Large Aperture Diameter: 0.18 in / 4.5mm
- Small Aperture Diameter: 0.06 in / 1.5mm
- Adjustment: Windage, approx. .75 MOA per click at 14.5 in sight radius
- Mounting Torque: 2 Nm / 17.7 in-lb max
- Style: Low Profile
What’s Included
- Kriss USA Defiance low profile rear flip-up sight
- Mounting screw
Frequently Asked Questions
Will the Defiance rear flip-up sight fit a standard AR-15?
Yes. It mounts to any MIL-STD 1913 Picatinny rail, so it drops onto a flat-top AR-15 upper the same way it goes on a Kriss Vector. Just make sure you leave rail space for a matching front sight and pair it with a compatible front for a proper sight picture.
Can I co-witness this sight with a red dot?
It is designed as a low-profile backup, so folded flat it sits well out of the way of a mounted optic. Depending on your red dot's mount height, it will typically co-witness in the lower third of the window, which is exactly how most people run a flip-up behind a red dot.
Why does the Defiance rear sight have two apertures?
The larger 4.5mm aperture is faster to acquire for close-range or low-light shooting, while the smaller 1.5mm aperture gives a tighter, more precise picture for longer shots. You can switch between them on the fly, and the sight still folds completely flat with either one selected.
How tight should I torque the mounting screw?
Keep it to no more than 2 Nm, which is about 17.7 in-lb. Over-torquing can damage the polymer body or the rail interface, so a torque wrench is worth using here. Snug and within spec is all you need for it to hold zero.






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