How to choose a good bottle preform ?

How to choose a good bottle preform ?

1. this bottle is recycled plastic bottle preform , when blowing bottle have white place

if you buy cheap bottle preform to blowing bottle , maybe you buy bottle preform is recycled plastic material .

2. new plastic pet material , this bottle preform blowing bottle all same .

no any while and no color different place . new plastic material price will expensive than recycled bottle preform .
so very cheap bottle preform don't buy . 

the best way use bottle preform try it , blowing some bottles .