Due to the change of the model, it becomes a floating stainless blade that makes it easier to use. Flipper is a unique Flipping, action called the Flipping, allowing you to change the blade surface without putting your hands into the aquarium, so you can enjoy cleaning moss while having fun. You will receive one stainless steel blade and one ABS blade with one of each purchase (FLIPPER and MAX only) ABS blades are sold for acrylic aquariums overseas, but acrylic is easy to scratch, so this product is sold for glass aquariums in Japan. We apologize for use with ABS blades for acrylic aquariums, but please use at your own risk. In addition, the stainless steel blade and ABS blade are not completely scratch on the glass aquarium, so please be aware of this before purchasing. Max 0.5 inches (12 mm) (recommended 8 - 12 mm)