Teeter EZ-Up Gravity Boots XL Plastic FEEL THE BENEFITS: Strengthen your core and legs with compression-free sit-ups, crunches, and inverted squats. Use pre-workout to warm-up muscles or post-workout to decompress and stretch. UNMATCHED COMFORT & SUPPORT: 5/8" thick soft foam liners and taller shell promotes even weight distribution to eliminate pressure placed feet. CUSTOMIZED FIT: 1 in. taller and 1.5 in. wider than standard Teeter Gravity Boots. Dual self-locking, ratchet buckles for adjustable, secure fit (best fits calves &gt;16 in. diam). Max user weight depends on supporting structure (300 lb for Teeter Inversion LIGHTWEIGHT & STRONG: Specialized materials ensure long-lasting quality and comfort. Each boot weighs just 2 lb! DuPont Hytrel shell and 40% glass/nylon alloy hooks for strength. FDA REGISTERED: Teeter decompression devices are FDA-registered and indicated for: back pain, muscle tension, herniated disc, sciatica, muscle spasm, and more!