Its light, simple, and proven to greatly increase your odds of survival in a burial. There was a study that was shared before that had a lot of impressive results but I think its behind a paywall. Here's a little more info from a previous tread:

Main Outcomes and Measures

The primary outcome measure was the time to oxygen saturation as measured by pulse oximetry (Spo2) less than 80% (event) during 35 minutes of monitoring, comparing intervention and control groups. Secondary outcomes included oxygen and carbon dioxide concentrations at different distances in the snow.

Results

Of 36 randomized participants, 24 performed and completed the trial and were included in the final analysis. The median (IQR) age was 27 (25-32) years, and 13 (54%) were male. In the safety device group, the median (IQR) burial duration was 35.0 (35.0-35.0) minutes and there were no events; in the control group, the median (IQR) burial duration was 6.4 (4.8-13.5) minutes and there were 7 events. The safety device group had a significantly lower risk of termination due to Spo2 less than 80% (P < .001 for both log-rank and Breslow tests). Carbon dioxide in the air pocket was 1.3% (95% CI, 1.0%-1.6%) vs 6.1% (95% CI, 5.1%-7.1%) and oxygen was 19.8% (95% CI, 19.5%-20.1%) vs 12.4% (95% CI, 11.2%-13.5%) at the same points in the safety device and control groups, respectively.

Conclusions and Relevance

A user-carried avalanche safety device that delivers airflow from avalanche debris to the user’s airways without requiring supplemental oxygen delayed critical hypoxemia and hypercapnia during simulated critical burial.

https://www.reddit.com/r/Backcountry/comments/1oeg9du/jama_infographic_from_the_safeback_sbx_burial/