I just looked them up on the net, the website says:

Q: Are there separate nappies for boys and girls?

A: Nature babycare is a unisex nappy available in six sizes.
And then found this:

Biodegradable, disposable nappies. Nature Babycare Nappies are available in Newborn, Mini, Midi, Maxi, Maxi Plus and Junior sizes
Maxi are 7-18kgs. I just started using these yesterday, so far so good. Except was used to Huggies and the Naty ones aren't as robust, I pulled the tabs off!

Found this on another site ... (nappyreview dot com dot au)

Newborn (2-5kg), 28 nappies
Mini (3-6kg), 46 nappies
Midi (4-9kg), 38 nappies
Maxi (7-18kg), 34 nappies
Maxi+ (9-20kg), 32 nappies
Junior (11-25kg), 30 nappies

1. Newborn - $11 per pack
2. Other Sizes - $18.50 per pack