iPad Pro Buying a Charger

[Orangeman13]

So I want to buy the 6 foot apple charging cable and then use the charging brick that came with the iPad. My concern is I like to charge my iPad slowly in on the box of the 6 foot Apple charging cable it says 240 W what determines the charging speed the brick or the cable?

 

[Genelec8341]

The cable is capable of carrying up to 240W with an appropriate charger.
If you use a 19W charger the iPad will charge at 19W.