What is a rattle?
This is a glass or plastic device in which small beads are embedded.

Depending on bead type, size and number, the sound varies from low to high pitched. The latter is inserted into the body of a soft lure.
When to use a rattle?
Although there are no specific conditions for using a rattle with a soft lure, I've found rattle-equipped lures to be more effective under certain conditions.
- During night fishing sessions, where the visual is absent, the sound compensates for this absence for the predator. The same applies to murky water.
- In windy conditions, the water surface is agitated, making lures less perceptible. Those fitted with rattle are better spotted by predators in the short term.

- To follow a wide area quickly, on fishing trips that involve covering as much ground as possible quickly, rattle-equipped lures are likely to attract predators from further away.
Animations to use
Rattles make noise when agitated. As a result, lures fitted with this device should be animated energetically.
Fishing on the fly, which consists of fishing between two waters by animating the lure with dry pulls, giving it an erratic swimming action, is very effective.
Lures such as Crazy Sand Eel or X Layer are adapted to this fishing method and are naturally equipped with rattle.

Scratch fishing, which consists of making contact with the bottom between each animation, is effective, and this is even truer with lures fitted with rattle. Each time it makes contact with the bottom, the rattle is agitated and emits a sound thanks to its beads. Predators lurking nearby are sure to come and see what's going on.
My selection of lures with which I use rattles
As mentioned earlier, some soft lures are equipped with original rattle. I'm thinking in particular of the Crazy Sand Eel by Fiiish and the X Layer by Megabass.

The vast majority of lures available on the market do not have a rattle, but they can all be fitted with one. Simply insert the rattle into the back of the lure, selecting a rattle adapted to the size of the lure.
Slugs, but also shads such as Black Minnow, which on some series are naturally equipped with them, are lures suited to the use of rattle.