These chairs have some serious manufacturing defects. 
I bought two in December for my home office. 
One came with stains in the fabric and holes in the seat for attaching the base were drilled in the wrong places so it was impossible to actually assemble it (wayfair sent a replacement for this one two months later). 
The second one fell apart with no warning after only two months of occasional use when my wife (tiny 120lb lady) sat on it; a weld in the base part just snapped. This is some absurdly low quality, definitely not worth the price.