Saurabh
If somebody offers to sell you a Dedakj oxygen concentrator for ₹1.2 lakhs, please don't buy it. And consider reporting the seller to the police.

This device was priced at not more than $150 in China till a month back. And when plugged into a patient with SpO2 89, it can't even lift them to 90. 7L/min my ass.

It can help a patient at 95 get to 97 (because the SpO2 curve is sinusoidal not linear). But anybody with SpO2 more than 90 shouldn't be provided external oxygen in the first place.