Black sandbag from GZ GYM, allowing weight adjustment with water or sand. - Brand: GZ GYM - Color: Black - Features: Adjustable weight with water or sand - Material: ABS resin Thank you for viewing. I purchased this for 15,800 yen on Rakuten, but I'm selling it because I don't use it much. I used sand as the weight when using it, so there is some dirt inside.