Standard mesh coils have one layer of mesh (a fine metal grid) that heats up when you fire the device. Dual mesh uses two layers of mesh in the coil assembly, which gives roughly double the heating surface area in contact with the liquid.

Why that improves flavour: more surface area means the liquid vaporises more evenly and thoroughly on each draw, producing a denser, more flavourful vapour with more of the flavour notes in the liquid being released simultaneously. It's a bit like comparing a larger frying pan to a smaller one for cooking – the wider surface gives a better result.

The trade-off is slightly higher power consumption and potentially shorter pod life with heavily sweetened liquids, since there's more area to accumulate residue. But for flavour it's a genuine improvement over single mesh.

That actually makes a lot of sense. I could see the pod looked different when I was fitting it but didn't understand why. Cheers for explaining it properly – not just "it's better" but actually how it works.