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Ultradyne
Overview
The Ultradyne USA C4 Offset Folding Rear Sight is designed for quick deployment and added versatility on the AR-15 platform. This folding sight features an offset design, allowing builders to maintain a low profile while providing rapid sight acquisition in various shooting scenarios. Commonly found in builds utilizing a carbine gas system and chambered in 5.56 NATO, it enhances the functionality of your rifle without adding unnecessary bulk.
Ultradyne USA C4 Offset Folding Rear Sight was the sixth most added rear sight on GunPartPicker in August 2026. Builders have been adding it to their builds on GunPartPicker since February 2026. All time, it is the seventh most added rear sight on the site. Builds with this rear sight are split between 5.56 NATO (58%) and .223 Wylde (17%), split between carbine-length (36%) and mid-length (36%) gas systems, and nearly all AR-15.
Availability is good: it was in stock at one retailer or another nearly every day in August 2026, and today 3 of the 4 retailers we track have it in stock. The best price drifted down from $225.43 to $159.99 over August 2026 without a real sale. Buying today, the lowest price is $225.43 at BattleHawk Armory, above August's low of $159.99, so a better deal may come back.
Updated · from real builds on GunPartPicker · Prices checked · refreshed daily across 31 retailers
We ranked every rear sight by how often it shows up in real builds on GunPartPicker.
Read the guide: AR-15 Rear Sight Guide →The part most often added in each category by the 98 builds that include this one
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Aggregated and anonymized data showing how builders use this product
Builds in the community that include the Ultradyne Usa C4 Offset Folding Rear Sight
| Build | Parts | Total |
|---|---|---|
 | 24 | $7000.58 |
 | 31 | $7359.61 |
 | 27 | $2299.24 |
 | 25 | $4826.82 |
 | 28 | $1107.32 |
 | 24 | $3516.61 |
 | 18 | $4732.65 |
2 global ratings
Top reviews
Ultradyne C4 offset folding rear sight runs at 45 degrees off the rail. No battery needed since its iron sights - battery life is essentially infinite. Folds completely flat. Solid backup behind an LPVO that doesnt work great at 1x.
Ultradyne C4 offset folding rear sight runs at 45 degrees off the main rail. No battery needed since its iron sights. Folds completely flat when not in use. Solid backup behind an LPVO at 1x doesnt always work for close range.
