-Can be filled with sand or water for safe punching and kicking-4 strong springs and an enlarged silencing layer for reduced noise -Upgraded Stable Sucking Base with 12 large strong suction cups -Multi-Layer Construction with high quality material -Free Standing - no need for hanging or drilling -Suitable for the whole family use to build strength-Wear-resistant fabric with tight stitching ensure a long time use-The Surface is waterproof and easy to cleanâ- Unique Shockproof System - Equipped w