Sprite SLC vs. ARC Cartridges, What’s the Difference?

What is the difference between the Sprite Royal All-In-One Cartridge (ARC) and the Sprite Sprite Slim-Line Shower Filter Cartridge (SLC)? According to your website, these both fit my shower head, which is a Sprite AM8-CM. Good question. The Sprite PureSpray all-in-one and Sprite Royale all-in-one shower filters both work with either the SLC or the ARC [...]