Valtteri Bottas says Pirelli's 2019 tyres feel similar to their predecessors.

For this year, the colour identification of the tyres has changed, with only 'hard', 'medium' and 'hard' tyres to be marked at each grand prix in the interest of simplicity.

Also the compounds have been tweaked.

But the difference that caught the most attention as winter testing began in Barcelona was that the brand new Pirelli tyres had a very shiny appearance.

"I don't know what it is, but they seem to be really shiny," Mercedes driver Bottas told Finland's MTV.

Pirelli later explained that the shine is due to the use of chrome moulds.

Bottas said: "They are not more slippery when you go out of the pits, they just look more shiny.

"In truth they are the same as last year. There's really no great difference," the Finn added.