KEMP USA 10-992 Head Blocks for EG Aquatic Spineboard are preferred to other blocks in the industry, extremely durable and will not damage if the board is dropped. Just one pair of blocks will last numerous seasons without needing to be replaced. They are compatible with the Aquatic EG Spine Board (Item # 10-982) or the Wood TG Spine Board (Item # 10-981) and are sold in pairs with the chin strap included.