I love my proto-X micro quadcopters. Unfortunately Estes does not sell a prop guard for this little bird. I created a propeller guard for the proto-x quadcopter. I use the prop-guard for indoor flying as it allows you to bump off of furniture. The guard also slows the response of the machine a bit, making it fun for novice flyers. The quadcopter weighs in at 11.257 grams. Flight time = 4.25 mins The bumper adds 0.971 grams. Flight time = 4.1 mins The prop guard adds 2.862 grams. Flight time = 3.5 mins To keep the weight down I made these parts to have 0.5mm walls and 1mm supports. It took a few crash tests to achieve the balance of weight vs. strength. I print these parts out of PLA clear: