FMW-501 Foldable Wind Screen (15cm)

Which stoves does this windscreen fit?

Because it is exactly 15cm (5.9in) tall, it is specifically designed for low-profile stoves that sit directly on the ground.
This includes remote canister stoves (where the gas line runs away from the burner) and ultralight alcohol/spirit stoves.

Can I use this with a stove mounted on top of a gas canister? (

ABSOLUTELY NOT. Never wrap a tight windscreen around a top-mounted canister stove (like a PocketRocket or Hornet II).
This 15cm screen will not reach the flame, and instead will trap intense heat directly against the pressurized gas canister, creating a severe risk of explosion.

Why use a windscreen if my stove is already powerful?

Even a light, continuous breeze strips immense amounts of heat away from your pot's surface. Using this screen can save 20–30% of your fuel on a multi-day trip.
That efficiency often means you can carry one less gas canister, saving you significant pack weight.