Topflite 100% natural NZ aquatic gravel, for coldwater and topicals. colour Dusk Size 4-6mm This auction is for 13kg approx This has just come out of my tank. It has been cleaned and boiled for 2 minutes to sterilize. It was a good amount in a 61 x36 cm tank with good depth for plant roots to establish. pickup Hornby Photo shows of stones in tank, black makes the plants and fish stand out.