Small - Red. Reduce carpal tunnel syndrome. Feels natural and offers maneuverability. Reduce fatigue while providing treatment. Provides support while reducing the stress on your joints and wrists. Can be used interchangeably with thumbs, middle and index fingers. Massage deeper and be able to work longer. Easily cleaned, lightweight, ultra-portable. Made in the USA. How Do I Know Which Size To Order? Take A Measurement Across The Joint In The Middle Of Your Thumb. If It Is Less Than 3/4”, Order Small - Red. If It Is Between 3/4” and 7/8”, Order Medium - White. If It Is Between 7/8” and 1 1/8”, Order Blue - Large. Summary: Thumbsavers Massage tools are used to enhance your productivity and longevity as a practitioner. As an affordable massage aid, it assists massage and physical therapists by providing support and reducing the stress on your joints and wrists while performing deeper tissue massages - its job is to protect your most valuable assets: your thumbs and hands. Thumbsavers are so unique that they cannot be called a "tool" because your thumbs and fingers are actually inside them. Thus, they have the right level of sensitivity & mobility that separates it from other 'tools' on the market. Fatigue, thumb, finger, and wrist pain will be no longer a problem. Thumbsavers can be used interchangeably with thumbs, middle and index fingers. Can be used for: Trigger point therapy, Deep tissue massage / neuromuscular therapy, Chair massage, Acupressure, Shiatsu, Thai massage, Reflexology, Equine massage, so much more. We find the best massage lubricants to use with thumbsaver. ** Please note that due to the differences in thumb shape and length, this tool may not fit every person / thumb as intended. If a different size / shape is needed, please us know and we will make sure you receive a replacement. **