Sjöställe i Stockholms skärgård

This accommodation is covered with S-certification for enhanced security

Stugknuten S-certification means that your landlord has chosen to provide you with as secure a transaction as possible. This accommodation must be paid for when you make your booking, but the rent is not actually paid out to your landlord until you have checked out. This extra security only applies if your booking and payment is made via Stugknuten.  
Read more here