No working phone number No working phone number. I paid for a machine and it is lost in the mail TTLIFE has done NOTHING to resolve the problem. They refused to return my money or ship another machine. TTLIFE blames the shipper yet they will not give me the name or phone number for them. RUN don't walk away from this company.

Great concedntrator - so lightweight and easy to take anywhere with you. I needed a concentrator that I could take with me on walks plus my automobile traveling. Lightweight and easy to handle. This NT-05 I purchased fit my budget, as for what I paid, I feel it has a lot to offer. Quiet, easy to use, affordable. I love it.

Great Product As a COVID survivor Great Product As a COVID survivor, I've come a long way with my recovery, relying on ventilators and oxygen supplementation post-hospitalization. Two years out, and I'm mostly back to myself, though I still need a little help at night. I'm really pleased with the NT-04 oxygen concentrator — it's been a reliable companion through my daily life. Now, I'm looking into getting a portable unit for travel. This device has truly supported my path to getting back to life as it was.

Very good company Very good company. I highly recommend the Varon machine. Quiet and I only have to use setting 3 to get my oxy level up Don't worry about negative reviews as they are inspired by competitors. DB LAWS MILFORD

I'm at loss on how to change the filter… I'm at loss on how to change the filter cotton in my NT-02, but after contact their customer service team, they promptly sent me a how-to video. They were both friendly and professional