How to tell the difference between good&bad extensions

The left side are my tressmatch remy human hair extensions 20"-22" 160g . The right side are my old local beauty supply hair extensions called evita hair extensions. (Horrible)

Top of the good hair extensions must be thick and full of hair .

Clips are secured with silicon under it for extra grip.

Bottom looks nice and silky also thick . It's thick from top to bottom. No split ends, no breakage,no nothing!!

BAD HAIR EXTENSION. Top looks hairless and damaged. Not silky or shiny .

Clips also have silicon but they are not secured .

The bottom is hairless,weak,split ends,not so natural. These hair extensions are not even good enough for people with thin hair.

Be very careful when buying extension. . The bad one on the left side cost me about 60-80$ . Got damaged in 1 week,was well taken cared of but still messed up.right side cost me 114$ worn 20x !