Price:$39.95
Like the RX800, the RX900 Competitor boasts our highest level of Oxysox® Compression Technology, coupled with TCK proDRI. However, for athletes who know the punishment of incessant impact and find themselves prone to hot spots and blisters, we’ve tacked on some extras–a high-density impact-absorbency cushion in the sole constructed with Coolmax®, well-known for its ability to transfer moisture and heat away from the skin; and a high-splice for added protection against abrasion, hot spots, and blisters. Thus, you get the best a graduated compression sock has to offer (maximum performance-enhancing mmHg ratings, ultra-lightweight support, superior moisture-management, and durability for the long haul) plus a dose of preventative maintenance to help you comfortably compete, train, or recover.
US Patents
- 5,898,948 / 6,032,296 / 6,173,452
testing shows the following benefits
- Higher VO2 levels
- Faster muscle recovery
- Reduced swelling and muscle fatigue
- Protection against cramps, strains, or sprains in the lower leg
popular uses
The RX900 offers our highest mmHg levels. This translates into robust support for:
- Triathlons
- Distance Running
- Cycling
- Bicycle Touring
- Cold-Weather Training
performance features
- Graduated Compression: 18-22 mmHg in the ankle tapering off to 14-18 mmHg over the calf
- TCK proDRI insulates and manages moisture while fighting odor and bacteria
- Ergonomic Coolmax® sole cushioning for comfort and impact absorbency
- Flat-knit body yields ultra-lightweight form
- Compression in foot reduces foot fatigue and increases circulation
- High-splice protects against abrasion, hot spots, and blisters
- Mesh instep aids in breathability
- Maximum Lycra support in the foot, ankle, and calf equals form retention, concentrated support, and injury protection
- Double welt top for comfort and fit
- Smooth toe seam adds comfort
available colors
- White
available sizes
- RX900 – Small (Men: 3-6 / Women: 4-7)
- RX900 – Medium (Men: 6-9 / Women: 7-10)
- RX900 – Large (Men: 9-12 / Women: 10-13)
- RX900 – XLarge (Men: 12-15)
care instructions
- Twin City products are best preserved when machine washed and dried on low heat.
- NO BLEACH
- Launder inside out to prevent pilling and fuzzing.





