For The DonJoy Reaction Knee Undersleeve take the measurement of your thigh and calf 6″ above and below your kneecap using a flexible type tape measure. Use the circumference you measure here to choose your size.
Note: The DonJoy Reaction UnderSleeve runs small. If you measure between sizes we recommend going up one size for optimum comfort and fit
Size Guide
| Size | Thigh |
| Small | 39-46cm |
| Medium | 47-53cm |
| Large | 53-59cm |
| XLarge | 60-67cm |
