Features: 1. The pulse oximeter for sports has 2-Direction Display adjustable. 2. Reliable accuracy and durability. 3. Automatic power off when no signal. 4. Small and light weight, convenient to carry. 5. Low voltage indicator, Real-time spot-checks. Specifications: Material: ABS Color: Bule Power by: 2xAAA Battery (not included) Package Included: 1 x Fingertip Oximeter for Sports 1 x Instruction Manual 1 x Portable Lanyard Notes: The battery installed in the device is in two opposite directions. When you install the battery, you need to check the positive and negative signs on the battery slot first, because the wrong polarity will cause the device to not work properly.