How it surfs
Tail choice is the real decision. The squash keeps more area for drive off the bottom in weaker surf; the swallow breaks that area up and loosens the board through the pocket. JS offers both at the same price.
Because most sizes are made to order, factor the build time in: JS quotes 4 to 6 weeks for PU and 14 to 16 weeks for PE, Carbotune and HYFI. If you want one for a specific trip, order early or buy a stock size.
Volume & sizing chart
Use the chart below as a starting point. Add half a litre if you are less experienced, subtract half a litre for a looser feel.
| Size | Volume | Rider weight | Best for |
|---|---|---|---|
| 5'7" | 24.3 L | 64 kg (Hiroto Ohhara reference) | Advanced |
| 5'8" | 25.6 L | 70 kg (Jeremy Flores reference) | Advanced |
| 5'9" | 27.8 L | 75 kg (Dusty Payne reference) | Intermediate+ |
| 5'6" | See JS chart | Under 62 kg | Advanced |
How it compares
| Board | Best at | Wave range | Aggregate score |
|---|---|---|---|
| JS Monsta 10 | Pro-level performance shortboard | Waist to overhead | 9.1 |
| JS Black Baron 3 | Dedicated small-wave groveler | Knee to head-high | 9.1 |
| JS Air 17 X | Everyday all-round shortboard | Knee to overhead | 9.2 |
Recommended fin setups
- Futures JJF Techflex — Balanced flex that suits the Monsta Box's medium rail.
- FCS II Performer Medium — Neutral, forgiving template for average surf.
Verdict
The Monsta Box 2020 is JS's everyday hybrid: enough lift and glide from the Blak Box side to work in average surf, enough drive and rail from the Monsta side to still surf properly when it improves. Stock 25.6 L test boards show it is meant to be ridden at close-to-shortboard volume.