My order has been in transit for over 80 days and when I tried to contact them via WhatsApp, they never replied. They only replied after I submitted a complaint through PayPal. Then they only provided the tracking information (that I already had) and said to be patient. No other assistance offered or provided. I had to make enquiries from both Chinese and NZ postal offices. Unfortunately, they only point at each other or say to contact the shipper. I am currently trying to get my money back from PayPal, but this appears to be a slow and difficult process. So due to my experience, I can't recommend 6mm. Use at your own risk.