AR15 Upper Receiver Cover

I came up with these covers because I often use a single lower with multiple uppers. Every time I went to the range, one of the greasy BCGs would slide out of an upper in my range box and make a mess of everything. To solve this (without bringing additional BCG tubes), I designed a cover that secures the BCG inside the upper. The cover only works when the BCG is inside because it uses two bar magnets to attach to the bottom and rear of the BCG. Uses a 60x10x5mm horizontally in the bottom (layer pause 102) and a 40x10x5mm bar magnet vertically in the rear (layer pause 224), you can get them on Amazon Boost MeThank You