Activity Monitors features: Ant + Bluetooth Heart Rate Monitor For Men And Women Ip67 Waterproof Sports Running Sensor With Chest Strap Adjustable Color: we send based on the color or size of the main image of the product page. Quantity：we send based on quantity on title, if there is no quantity in the title, we send based on description. This adjustable heart rate chest strap is suitable for many occasions, such as running, jogging, fitness, sports, etc. The heart rate chest strap is designed to track and record data such as heart rate and calories. The heart rate belt is easy to use, just wear it on your chest. The heart rate belt is designed with an adjustable strap that allows you to adjust between 25.2 and 33.8 inches. The heart rate belt adopts IP67 waterproof, it is not easy to be damaged by sweat and rain. Specification: Material: leather + electronic components. Colour: Black. Dimensions: 5.2x3.4x1.4 inches. Note: Due to different computer resolutions, there may be some color distortions. Due to different hand measurements, there may be slight errors.