This item has been discontinued. We recommend Grodan Stonewool Delta Starter Mini-Blocks -- 1.5 inch x 1.5 inch x 1.5 inch as a replacment. • Size: 1 x 1 • Excels in all hydroponics systems currently designed for aggregate • Exceptionally versatile and can be used to fill any size container regardless of shape or volume • A nearly infinite amount of open cell voids encourages dense root development Special Features: • Easily fill any size pot or container regardless of size or shape • Proprietary open cell design allows for air to move freely through the cubes, ensuring the stem stays dry and healthy while the roots beneath receive ambient circulation • Non-wicking design combined with inherent structural voids allows the grower to feed more often, leading to healthier plants and better harvests • pH neutral and requires no conditioning or continuous adjustment of your bath due to media influence • Inert and imparts nothing to your nutrient solution. This allows the grower to start from scratch when developing a feeding schedule. BPA Free. • Can be used as an amendment to increase the overall performance of preexisting media. • Perfect for all hydroponic growers regardless of scale or scope