Convoy M21B vs Streamlight ProTac 2L-X USB size comparison
The Streamlight ProTac 2L-X USB is 10.9 mm (0.43 in) shorter than the Convoy M21B, and 8.8 mm narrower at its widest point. Weights are published on different bases (with battery vs listed), so compare them with care.
The Streamlight ProTac 2L-X USB is 10.9 mm (0.43 in) shorter than the Convoy M21B, and 8.8 mm narrower at its widest point. Weights are published on different bases (with battery vs listed), so compare them with care.
Dimensions
| Convoy M21B Check price ↗ | Streamlight ProTac 2L-X USB Check price ↗ | |
| Length | 141.5 mm (5.57 in) | 130.6 mm (5.14 in)−10.9 mm |
| Head / width | 35.7 mm (1.41 in) | 26.9 mm (1.06 in)−8.8 mm |
| Body | 27.1 mm (1.07 in) | 23.9 mm (0.94 in)−3.2 mm |
| Weight | 120 g listed | 125 g with battery |
| Battery | 21700 | 18650 / 2x CR123A |
| Max output | — | 500 lm |
| Throw | — | — |
| Type | EDC | EDC |
| Price | $48.99 at flashlightgo.com, as of Nov 4, 2026 | $83.05 at batteryjunction.com, as of Nov 4, 2026 |
| Source | flashlightgo.com sourced Output depends on LED option | batteryjunction.com sourced |
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M21B vs ProTac 2L-X USB: how they differ
Size and weight
The Streamlight ProTac 2L-X USB is the shorter light: 130.6 mm (5.14 in) against 141.5 mm (5.57 in), a difference of 10.9 mm (8%). At its widest point the Streamlight ProTac 2L-X USB is 8.8 mm slimmer (26.9 vs 35.7 mm). Weights are published on different bases (Convoy M21B: 120 g listed; Streamlight ProTac 2L-X USB: 125 g with battery), so they are not directly comparable.
Brightness and throw
The Streamlight ProTac 2L-X USB is rated at 500 lm; we have no published maximum for the Convoy M21B. Output for the Convoy M21B depends on the LED option chosen.
Battery
The Convoy M21B runs on a removable 21700 battery; the Streamlight ProTac 2L-X USB runs on removable 18650 / 2x CR123A batteries. For scale, a 21700 cell is about 21 × 70 mm and a 18650 about 18 × 65 mm (nominal).
Price
When we checked on Nov 4, 2026, the Convoy M21B was $48.99 at flashlightgo.com and the Streamlight ProTac 2L-X USB $83.05 at batteryjunction.com, so the Convoy M21B cost $34.06 less. Prices change often, so check the current price before you buy.
Type
Both are EDC lights in our catalog with a tube body.
Which should you buy?
Choose the Streamlight ProTac 2L-X USB if you want a shorter light (10.9 mm shorter) and a slimmer profile (8.8 mm narrower). On the specs we track, the Streamlight ProTac 2L-X USB is ahead or level everywhere; the Convoy M21B makes sense mainly if its price, interface or a feature we don't track suits you better. We compare published size, weight, output, throw and battery only, not runtime, interface or build quality.
Check price ↗ Convoy M21B Check price ↗ Streamlight ProTac 2L-X USB
We may earn a commission from these links, at no cost to you. Rankings are never paid for. Disclosure
M21B vs ProTac 2L-X USB FAQ
Which is smaller, the Convoy M21B or the Streamlight ProTac 2L-X USB?
The Streamlight ProTac 2L-X USB is the shorter light: 130.6 mm (5.14 in) against 141.5 mm (5.57 in), a difference of 10.9 mm (8%). At its widest point the Streamlight ProTac 2L-X USB is 8.8 mm slimmer (26.9 vs 35.7 mm). Weights are published on different bases (Convoy M21B: 120 g listed; Streamlight ProTac 2L-X USB: 125 g with battery), so they are not directly comparable.
Which is cheaper, the Convoy M21B or the Streamlight ProTac 2L-X USB?
When we checked on Nov 4, 2026, the Convoy M21B was $48.99 at flashlightgo.com and the Streamlight ProTac 2L-X USB $83.05 at batteryjunction.com, so the Convoy M21B cost $34.06 less. Prices change often, so check the current price before you buy.
Do the Convoy M21B and Streamlight ProTac 2L-X USB use the same battery?
The Convoy M21B runs on a removable 21700 battery; the Streamlight ProTac 2L-X USB runs on removable 18650 / 2x CR123A batteries. For scale, a 21700 cell is about 21 × 70 mm and a 18650 about 18 × 65 mm (nominal).
Compare Convoy M21B with similar lights
Compare Streamlight ProTac 2L-X USB with similar lights
More
Sources
- Convoy M21B: specs from manufacturer published specs as listed by flashlightgo.com. Price $48.99 from flashlightgo.com, checked Nov 4, 2026; prices change often.
- Streamlight ProTac 2L-X USB: specs from manufacturer published specs as listed by batteryjunction.com. Price $83.05 from batteryjunction.com, checked Nov 4, 2026; prices change often.
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