Review on PROMiXX MiiXR+ PLUS Electric Protein Shaker Bottle - Device-Charging Vortex Mixer for Smooth Shakes & Supplements, Shake Bottle Blender, Mixer Cup, 20oz Tritan (Stealth Black) by Heidi Smith

I've been a huge PROMiXX fan for a long time and have been buying their faucets for years. A few months ago I thought it was time to switch to a stealth model as it seemed more premium and my other bottle was dead. I was impressed with the bottle which worked great until about two weeks ago when I noticed that the rubber stopper covering the charging port/USB hub wouldn't stay closed. No matter how many times or how hard you squeeze it, it just keeps sliding back out slowly. I'm worried that at some point something will happen to the bottle in my bag or backpack, causing the rubber valve to pop off. As a solution I used tape to hold it in place. Unfortunately, this makes the bottle look awful. I'm always very careful with my shaker and have never dropped it or anything like that. I wouldn't expect this quality from a $50 bottle.