Your Kayfun 5 Squared doesn't need much maintenance. However, the most sensitive part on the K5 squared is decidedly the glass tank section.

Straight from Svoe Mesto, this made-in-Germany glass tank section is a direct fit for your K5 squared. Sold individually per order, you should always have at least one in your stockpile. You know, just in case.

Sold individually - one glass per order. Requires the Kayfun 5 Squared RTA to operate.