What is a hardbait
A hardbait is a rigid lure made of hard plastic or wood, with a lip at the front and hooks on split rings. Everything it needs to work is already built in: it needs no separate weight and no extra rigging.
What it is made of
The most common material is moulded plastic: it produces identical copies one after another and leaves a hollow inside. Wooden models are turned one at a time, and that is exactly why two wooden lures that look the same can work a little differently — the density of wood is not the same all the way through.
Where the action comes from
The flow presses on the lip, the body deflects, the lip goes off balance — and the lure wobbles from side to side. With no forward motion there is no action at all: a hardbait lying still does nothing.
Hooks and rings
Treble hooks are hung on split rings rather than fixed rigidly: that way a hook can be swapped, and it is free to turn as it comes loose. The ring is a separate link in the chain of strength, and it fails no less often than the hook itself.
The cavity inside the body
A moulded hardbait is hollow inside, and it is exactly that cavity that sets its buoyancy: however much air is in it, that is how the lure behaves on a pause. Weight is added inside it too, to shift the centre of gravity back and cast the lure further; in some models this weight is loose and rolls inside the body as it is cast.
The rattle chamber
Many models have a cavity with small balls inside the body: on the retrieve they roll around and make a rattle. Not every lure has a chamber, and it is no mark of quality — it is simply another channel through which the lure gives itself away.
What is printed on the lure itself
Length in millimetres and weight in grams are printed on the body or on the box. Weight here is not about depth but about casting: a light lure with a big lip casts poorly even when it holds its depth well.
How it is stored
Exposed treble hooks catch on each other, so hardbaits are kept in compartments rather than loose. Soft lures are kept separately from them: the plasticiser in silicone eats through the lacquer coating at the point of contact, and that is the costliest storage mistake.
How it differs from a spinner
A spinner works by reflected light and its own rotation, a hardbait by shape and its lip. The main practical difference is elsewhere: a spinner has no running depth of its own, but a hardbait does, and that is exactly why they are fished differently: a spinner is held at depth by retrieve speed, a hardbait finds its own.