The Chirp Wheel+ Stretch & Massage Rollers are great for anyone dealing with a stiff back or poor flexibility. The set includes three wheel sizes - a 10" wheel for larger muscle groups and spinal relief, a 6" wheel for targeting knots and tight spots and a 4" wheel for precise pressure on the neck and back. Spinal Canal technology helps reduce pressure on your spine, so you can roll more comfortably. Plus, the four-way stretch design and EVA foam cushioning help ease tension, improve mobility and support better posture.Supports up to 227 kg