What charging cube does an iPad Pro 10.5" second generation need?

I recently bought an Apple iPad Pro 10.5" second generation second hand and it doesn't come with a charger. I already have a USB-C to lightning charging cable with me but I still need a charging cube for it. I was just wondering what the wattage of one should be for the cube for the iPad I bought because I honestly have no idea. I barely know anything about iPads (especially the Pro models). I would really appreciate somebody telling me what the wattage amount should be for one or giving me suggestions of what cube to buy for it. Thanks!

-Conner