Convoy M21B vs RovyVon S3 Pro size comparison
The RovyVon S3 Pro is 22.5 mm (0.89 in) shorter than the Convoy M21B, and 6.7 mm narrower at its widest point. Weights are published on different bases (listed vs listed), so compare them with care.
The RovyVon S3 Pro is 22.5 mm (0.89 in) shorter than the Convoy M21B, and 6.7 mm narrower at its widest point. Weights are published on different bases (listed vs listed), so compare them with care.
Dimensions
| Convoy M21B Check price ↗ | RovyVon S3 Pro Check price ↗ | |
| Length | 141.5 mm (5.57 in) | 119 mm (4.69 in)−22.5 mm |
| Head / width | 35.7 mm (1.41 in) | 29 mm (1.14 in)−6.7 mm |
| Body | 27.1 mm (1.07 in) | 29 mm (1.14 in)+1.9 mm |
| Weight | 120 g listed | 150 g listed |
| Battery | 21700 | 18650 |
| Max output | — | 2,800 lm |
| Throw | — | 130 m |
| Type | EDC | EDC |
| Price | $48.99 at flashlightgo.com, as of Nov 4, 2026 | from $79.95 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 S3 Pro: how they differ
Size and weight
The RovyVon S3 Pro is the shorter light: 119 mm (4.69 in) against 141.5 mm (5.57 in), a difference of 22.5 mm (16%). At its widest point the RovyVon S3 Pro is 6.7 mm slimmer (29 vs 35.7 mm). Weights are published on different bases (Convoy M21B: 120 g listed; RovyVon S3 Pro: 150 g listed), so they are not directly comparable.
Brightness and throw
The RovyVon S3 Pro is rated at 2,800 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 RovyVon S3 Pro runs on a removable 18650 battery. 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 RovyVon S3 Pro from $79.95 at batteryjunction.com, so the Convoy M21B cost $30.96 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 RovyVon S3 Pro if you want a shorter light (22.5 mm shorter) and a slimmer profile (6.7 mm narrower). On the specs we track, the RovyVon S3 Pro 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 ↗ RovyVon S3 Pro
We may earn a commission from these links, at no cost to you. Rankings are never paid for. Disclosure
M21B vs S3 Pro FAQ
Which is smaller, the Convoy M21B or the RovyVon S3 Pro?
The RovyVon S3 Pro is the shorter light: 119 mm (4.69 in) against 141.5 mm (5.57 in), a difference of 22.5 mm (16%). At its widest point the RovyVon S3 Pro is 6.7 mm slimmer (29 vs 35.7 mm). Weights are published on different bases (Convoy M21B: 120 g listed; RovyVon S3 Pro: 150 g listed), so they are not directly comparable.
Which is cheaper, the Convoy M21B or the RovyVon S3 Pro?
When we checked on Nov 4, 2026, the Convoy M21B was $48.99 at flashlightgo.com and the RovyVon S3 Pro from $79.95 at batteryjunction.com, so the Convoy M21B cost $30.96 less. Prices change often, so check the current price before you buy.
Do the Convoy M21B and RovyVon S3 Pro use the same battery?
The Convoy M21B runs on a removable 21700 battery; the RovyVon S3 Pro runs on a removable 18650 battery. 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 RovyVon S3 Pro with similar lights
More
Sources
- Convoy M21B: specs from manufacturer published specs as listed by flashlightgo.com. Drawing: outline from published specs. Price $48.99 from flashlightgo.com, checked Nov 4, 2026; prices change often.
- RovyVon S3 Pro: specs from manufacturer published specs as listed by batteryjunction.com. Drawing: outline from published specs. Price from $79.95 from batteryjunction.com, checked Nov 4, 2026; prices change often.
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