Compatibility: Microsoft Surface pro7/6/5/4/3, Surface Laptop1/2/3, Sruface Book1, Surface Go1/2/3. This cable is compatible with Surface Pro 8/9 Surface Laptop 5, but due to technical limitations, the system will show "Slow charger is connected", but the power is enough that you can work and entertainment normally. Charging only: It should be noted that this product can only be used for charging surface devices, data and HDMI cannot be transmitted. Each unit is inspected and tested prior to shipment. We stand behind our products with a 12 month worry-free warranty. Requirement: This cable requires an USB-C charger or charging bank that support 45W 15V3A output. Female USBC charging cable also need the USBC cable can carry 3A current. Doublecheck your USBC charger to ensure that it lists "15V/3A" in the specifications. Some PD chargers didn't support the cable, most phone charger wouldn't support the cable. It's recommended that use the cable together with our GaN 3-Port USBC charger, avoid incompatibility problems. Please find the link in the page details. TROUBLESHOOTING: 1. If the LED flashes: it means that your charger has insufficient power. Please use a USB-C charger of 15V3A and 45W or above. 2.Phone and Pad Charger can't work: Due to lack of 15V output or less than 45W, Most phone charger wouldn't work with this cable. Older Mcbook Charger do not meet the requirement, such as A1718, A1719, A1540, A1882. 3.If the LED don't light up: Please try another 15V/3A 45W charger. If it still doesn't work, please find us via seller profile. Allows you charge your Surface devices via 45W 15V3A USB-C Power Delivery (PD) wall charger or power bank, you only need to bring a USBC charger to charge many devices including Surface on the go. It is very lightweight and portable. It can also be used as a spare charger.