Quick answer: This is a gear care product from Mares.
Gear lasts much longer when it's rinsed, dried and stored properly. Good hangers and care products protect big-ticket items like extended-size wetsuits, drysuits and BCDs, which aren't easy to replace off the rack.
Follow the maker's instructions, and use products made for dive gear rather than household substitutes. Read How to Clean a Dive Regulator. More options: Dive Accessories.