Review on Solar-Powered Rock Outdoor Lights: 4-Piece All-Weather Faux-Stone LED Solar Lights Set (Black) by Pure Garden - Ideal for Paths, Gardens, and Landscaping by Souly Buddy

I use these lamps for landscape and plant decoration; They work for if you're okay with some light lighting. They will not light the way to go. I put one up in my conservatory to accent the late evening plants and flowers and I love it. You'll also love the fact that you can easily move them around and place them where they get the most direct sunlight. I didn't feel they had enough light around my pond, but that's a preference. Not sure about sustainability, but they're inexpensive, attractive, and easy to blend into the landscape.