Tokyo Marui Electric Gun Boys I used it to install the stock side sling of SOPMOD. When it glows red on the stove, it turned discolored into a bluish black and it felt nice. Since 4 mm reinforced hole is available in the stock, cut the threaded part to an appropriate length and fix it with the attached washer and nut. There was nothing to worry because two washers and two nuts are included. I feel a bit over-spec for the body of the pla, but I also like the texture, I like it.