What it does
During sandstorm, Sand Force gives the holder's Rock, Ground, and Steel moves a ×1.3 power boost. The holder is also immune to the 1/16 HP chip that sandstorm deals each turn to non-Rock, non-Ground, non-Steel types.
The 1.3 boost stacks multiplicatively with STAB. A Ground-type Excadrill using Earthquake in sand gets ×1.5 (STAB) × ×1.3 (Sand Force) = ×1.95 total. That's significant — closing in on a ×2 multiplier on what's already a wide-hitting move.
The boost disappears the moment sandstorm ends or is suppressed. No sand, no Sand Force.
Who runs it
Excadrill (2%) is the textbook Sand Force user. Ground/Steel typing means Earthquake, Iron Head, and Rock Slide all qualify for the boost. The competing ability is Sand Rush — doubled Speed in sand — and many sand teams prefer Sand Rush because Speed is a scarcer resource than raw power. The 2% reflects its current position in the Champions format.
Hippowdon (2%) is usually the sandstorm setter via Sand Stream and doesn't typically run Sand Force itself — when it does, the intent is hitting harder in the sand it creates rather than just sustaining it.
How to use it
Sand Force requires sustained sandstorm. Build around a reliable setter — Hippowdon with Sand Stream, or Smooth Rock to extend turns. Once the sand is up, every Rock/Ground/Steel move the holder uses gets the free 1.3 multiplier without spending an item slot.
In doubles: Hippowdon sets sand, Excadrill runs Sand Force and puts out boosted Earthquakes. The synergy is direct. The limitation is that your team architecture commits to a weather that the opponent can disrupt with their own weather or a Cloud Nine / Air Lock carrier.
Tips & strategy
Sand Force vs Sand Rush is a speed vs power decision. Most sand teams lean toward Sand Rush because outrunning the opponent often matters more than hitting 30% harder. If your team already has speed control handled elsewhere, Sand Force is the damage ceiling option.
Life Orb stacks with Sand Force — ×1.3 from the ability, then ×1.3 from the item. That's a large raw damage number. The 10% HP recoil per turn factors into how many turns the holder can actually stay on the field, so the calculation isn't pure upside.
Any form of weather removal or suppression shuts Sand Force off entirely. Know what your opponent's weather plan is before committing to a sand-dependent output strategy.