The SUNSUN SC-15 is a long CO2 diffuser designed for aquariums. While I don’t have specific information about this exact model, I can provide details based on similar SUNSUN CO2 diffusers:
Key Features

Made of high-quality glass
Long design for efficient CO2 distribution
Ceramic plate for creating fine CO2 bubbles
Suitable for planted aquariums

Benefits

Distributes CO2 evenly in the aquarium for healthy plant growth
Creates thousands of uniform, small bubbles for effective CO2 dissolution
Durable and aesthetically pleasing
Easy to install and maintain

The long design of the SC-15 likely allows for better CO2 distribution across a larger area of the aquarium compared to smaller diffusers. This can be particularly beneficial for larger tanks or those with dense plant growth. While glass diffusers are effective, they do require regular cleaning to maintain optimal performance, as they can accumulate algae and mineral deposits over time.