Take on any activity with confidence and comfort with CoreKnit-your go-to basic band at our most affordable price. Includes a Band, Hook, Clasp, and Fast Link(TM) slider that makes swapping bands easier than ever. Compatible with WHOOP One and WHOOP Peak -membership not included. CoreKnit is not ECG capable. DESIGN: DESIGNED FOR ULTIMATE COMFORT: CoreKnit is designed to be lightweight and flexible for all-day comfort PERFORMANCE KNIT: CoreKnit is made with our performance-ready knit, so that you can take on any workout or activity SWITCH UP YOUR STYLE: CoreKnit is available in a range of colors, so you can match your band to your personal style-made easy with Fast Link(TM) technology FULLY ADJUSTABLE: With a completely adjustable band, you can easily tighten or loosen CoreKnit to find your perfect fit