This is a Experimental swept grid fin designed for model rockets. I have ran many tests, and it works pretty well! This was our prototype for a while under the Propulsive Landing Research Project before being replaced with an different design currently under testing. This particular fin went through several torture tests, acing them all. We mounted it onto our Decent Research Vehicle (DRV, the vehicle in the picture) and dropped the whole rig without parachutes from 25 ft. The fins successfully stabilized the vehicle and had minor damaged ( small parts chipped). We really thought it would't survive at all though! The fins deploy via a nichrome wire connected to a flight computer pyro output. The wire heats up cutting a rubber band that wrappes around all the folded fins. Please note these fins are experimental, so use at your own risk. They are swept for improved performance at low airspeed and to reduce bow-shock. DO NOT use for high air speed applications, for the fins deploy toward the wind, and under high airspeeds would fold back and fail to deploy. I hope you like it!