Dodo Juice Blue Velvet Pro (Hybrid carnauba wax suitable for dark coloured cars)
Blue Velvet Pro is the supercharged offspring of Blue Velvet and Red Mist spray sealant, in other words, it's probably best classed as a wax/sealant hybrid. That means it's a dark coloured wax suitable for blacks, blues and other darker coloured paintwork - but it has boosted durability thanks to the sealant ingredients.
If you get, say, 2 to 3 months of protection from standard Blue Velvet, you'd be looking at about 3 to 5 months from the Pro version.
Whether you're stepping up from normal Blue Velvet, or just want a more durable wax from the off, this is a great choice.