Classic
The Primary Arms Classic 21mm Micro Reflex is an open emitter pistol optic on the RMSc footprint, offered with a 3 MOA Dot reticle in red. The window measures 0.55 x 0.80 in, and the aluminum housing measures 1.6 x 0.98 x 1.03 in and 1 oz. It runs on a CR2032 cell that requires removing the optic to change, and adds shake awake and night vision settings. Measured against the 311 pistol optics in the index, it lands in the lightest quarter for weight (1 oz), in the smallest quarter for window area (0.44 sq in), and among the least expensive 10 percent for price ($150). It is one of 61 entries in the index that qualify as a RMSc footprint optic. The closest listed comparison is Primary Arms Classic 21mm Micro Reflex Gen II, the same brand's RMSc footprint optic, priced at $160.

| Series | Classic |
| Reticle color | Red |
| Reticle options | 3 MOA Dot |
| Optic Removal for Battery Change | Yes |
| Window Size (in) | 0.55 x 0.80 |
| Enclosed | No |
| Footprint | RMSc |
| Battery | CR2032 |
| Solar Failsafe | No |
| Shake Awake | Yes |
| Night Vision Compatible | Yes |
| Material | Aluminum |
| Weight (oz) | 1 |
| Dimensions (in) | 1.6 x 0.98 x 1.03 |
| Country of Manufacture | China |
| Average Price | $150 |
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