Premium Material: The scuba tank boot and cap are made of PP materials, providing long service life. Diameter: 15.7 cm / 6.18 inches. Design: The diving accessories feature a dense groove design on the inner side to help prevent tank slippage. Use: The flat bottom protector helps safeguard the base of your cylinders and may assist in extending the life of air tanks. Efficient Drainage: The tank includes drainage channel holes that allow water to drain quickly, making it suitable for underwater activities. Upright Storage Protection: The upright storage protective cover supports vertical storage and protection of standing air cylinders. Specification: Material: PP Size Chart: Diameter: 15.7 cm / 6.18 inches Package Includes: 1 x Scuba Tank Cap 1 x Scuba Tank Boot Note: Please allow slight variations of 1-2 cm due to manual measurement.