I waterproofed my 645mg by opening it up and putting a ring of die-electric grease around the top where the servo horn attaches then put the top back on so it sandwiches the grease, then used a conformal coating like liquid electrical tape around all the seams, and the body screws, works great, did the same to my new Savox SA-1231S. The Hi-Tec worked great for an SCX-10, but for my 1/6 Jeep at 14lbs I needed to upgrade to the Savox.