Dear, All our products are original imported chips, which have been strictly tested and packaged,Quality is absolutely reliable. About capacity: 8GB=approximately 7.4GB-7.6GB 16GB=approximately 14GB-15GB 32GB=approximately 28GB-30GB 64GB=approximately 58GB-60GB 128GB=approximately 116GB-120GB 256GB=approximately 228GB-236GB The factory capacity of hardware manufacturers is as follows:1MB=1000KB,1G=1000MB,while our operating system adopts binary algorithm,so there is a difference between the display capacity of memory card and the nominal capacity,which is a normal phenomenon (1MB=1,000,000bytes). If you have any questions, please leave a message, we will have professional customer service for you.Thank you!