The brand is Simr, but I think there are only 3 or 4 meters that are sold as whitelabel and rebranded a thousand times. I think it was around $30. Outside it m

The brand is Simr, but I think there are only 3 or 4 meters that are sold as whitelabel and rebranded a thousand times. I think it was around $30. Outside it measures around 400ppm so the base point is good. Inside it measures 480ppm with good ventilation. When someone farts it goes to 2000ppm for a while. So I think it measures 'alright'.