This is a ReFa Fine Bubble Shower Head. The switch button is a little stiff, but the modes can be changed. There may also be an issue with water pressure. The shower I was using had quite strong water pressure, and the switch button felt stiff even immediately after replacing it. When the switch doesn't work well, using the method described in the included instruction manual (stopping the water and operating the button) will allow you to switch the shower modes smoothly. I purchased it from the official website, so it comes with a certificate. Thank you. - Brand: ReFa - Product Name: Shower Head - Model Number: RS-AF15A - Color: Silver - Accessories: Box, Instruction Manual