I have been more than happy to wear the whole package (Back and Chest Protector with Body Protection Sleeve) on recent eMTB rides. I don’t actually sweat too much on those rides, as I tend to go Boost mode everywhere, so breathability isn’t too much of an issue. The full package isn’t so breathable that i’d wear it for regular mountain bike rides, at least not during the summer months anyway. I’ll be limiting its use to chairlift and shuttle days, and eBike riding. The AirFlex Back and Chest Protector alone is bearable for regular riding, even in summer, especially as it works so well with a Hip Pack. The AirFlex gear doesn’t feel weighty when I’m wearing it, but I weighed it nevertheless. The AirFlex Back and Chest Protector weighs 760g on my Park Tool Scales. The AirFlex Body Protection piece, i.e the torso sleeve with shoulder and elbow pads, weighs 432g. That gives a grand total of 1192g, or 1.19 kg. It might sound a little on the heavy side, but I can assure you it carries its weight well.
https://bikerumor.com/review-leatt-airflex-review-chest-protector-and-body-armor/
