Compatible with Samsung galaxy note 8,big enough even if your device has been put into other protector case .Designed specifically to easily connect headphones and provide full access to all phone ports and sensitivity Water-resistant neoprene and PVC screen protector protect your smartphone from scratches,dirt and sweat in outdoors, installed in seconds. Designed to twist and bend but will not lose the original shape. Adjustable Velcro band supports a wide range of arm girth from 10" (25.4cm) to 15" (38.1cm). Adjustable velcro strap protects and stabilizes device without slipping or constricting.

1/ Universal Sports Arm Band for Phones with their cases: Fits 3.5'' to 5.1'' cell phones (such as iPhone 4s, 5/5s/SE, iPhone 6/6s/7/8), with all cases such as OtterBox Defernder cases. Also fits iPhone X with Otterbox Commuter cases, and Samsung Galaxy S8, S7, S6, A5, A3 with slim cases on. See Product Description below for more compatible smartphones and cases. 2/ Premium Quality Materials and Universal Arm sizes: Made of Ultra lightweight, stretchable, soft skin-friendly, breathable Lycra and neoprene. Also, hand washable, water resistant, sweat proof and eco-friendly. Grip with compatible keeps the band firmly on your arm during at gym, workouts and running. So you can focus 100% on your performance comfortable. In addition, two dual-slot adjustable Velcro will fit arm size from 9'' to 16''. 3/ Reflective stripe for safe running in low light conditions. Built-in reflective stipe around the transparent window, provides the visibility in low light condition and keep you safer when running or walking at night or in the early morning.