DIY reef inserts are made of high quality Eco-friendly materials that will last many years with very little up keep.The best part about these bases are that they can be interlocked or stack-able to allow the aquarist to move their reef inserts into a larger tank and build off of their existing bases to a larger more spectacular display.There are five rock bases that can be plugged to fit your decor with bright and vibrant colors or muted and more natural colored corals.