I'm selling this because I received it as a gift but don't think I'll use it. It's unopened. It's compatible with some Huawei smartwatches and provides very detailed data when connected. You can get more in-depth information than your watch provides, such as running form and what happens when you slow down in the second half of a run (hang time, stride length decrease, foot landing angle, etc. - the photos show some examples). Please purchase only if you know how to use it. * I have a total of 3 in stock. If you buy multiple items, I will discount the shipping cost, so please mention it in the comments section. *** The following is from the original seller *** Brand: HUAWEI Model Name: S-TAG Style: Smartwatch Color: Silver Features: Accelerometer, Multi-sport tracker, IP68 dustproof and waterproof Manufacturer's HP Retail Price: ¥9,680 Amazon Price at the time of listing: ¥8,600 HUAWEI S-TAG - Improve Running Form - Scientific Running Analysis - Professional Form Check - Lightweight and Compact Design (approx. 7.5g) - IP68 Dustproof and Waterproof [Compatible Products] HUAWEI WATCH GT Runner / WATCH Ultimate / WATCH Buds / WATCH GT Cyber / WATCH GT 3 SE / WATCH GT 3 PRO / WATCH GT 3 / WATCH FIT 2 [13 Running Form Metrics*7] Waist: Average GCT balance, average vertical oscillation. Foot: Average cadence, average stride length, landing method, average ground contact time, average flight time, average ground contact time/flight time ratio, average dorsiflexion, average swing angle, average landing impact, average vertical load rate. Foot + Waist: Average vertical oscillation ratio [Scientific Running] A brand-new sports sensor. The innovative design allows you to attach it to your feet or waist, enabling professional sports monitoring in various situations. Make sports easier and more professional with the HUAWEI S-TAG. [Professional Running Form Analysis] The unique algorithm, developed in collaboration with specialized institutions, analyzes runners' form and suggests improvements.