Note: Some smart phone could only support music switch by + and - button, but not support volume control. Such as, OPPO f1s and R9s. ES-2 could not compatible with Nexus 6P.Click here to check customer review: https://techaeris.com/2017/10/23/blitzwolf-bw-es2-review-fantastic-dual-dynamic-driver-sound/What does Dual Dynamic Driver mean?Not all earphones with two speakers are called as Dual Dynamic Driver earphone.The Dual Dynamic Driver earphone is not merely embedded with two dynamic drivers in a single earphone; it even uses frequency division technology to output bright treble and deep bass respectively. It has ultra high voice resolution, which can better present the sweet or hoarse voice and other details. In low frequency, the dual dynamic drivers are better than the balanced armature driver in the sense of quantity, which is easier to present the dynamic sense of music. Therefore, the Dual Dynamic Driver earphone not only adds a speaker on the ordinary earphone, accordingly it produces a shock effect comparable to that of the balanced armature driver earphone in the sound quality.100% Hot and High QualityWe will carefully test every item before shipment.Notes:Due to manual measurements, please allow an error of 1-3 cm.Due to problems between different monitors, the image may not reflect the actual color, please refer to the actual product.If there is a problem with the product, please contact us.Thank you for understanding.FEEDBACK:1.If you are satisfied with our products and services,please leave your postive feedback and 5 stars.2.If you don't satisfied our products,pls contact us before you leave negative feedback.we guarantee we will 100% slove any problem for you and make you satisfied.SERVICE:1.We care about our valued customers,and will always try to help you,hope to establish long business with you.2.Please contact us by Jumia Customer service before leaving any negative feedback or opening and dispute on the site. Please give us the opportunity to resolve any problem.Thank you.