Master Series Dark Invader Metal and Silicone Anal Plug Large from XR Brands. Feel the weight of this metal and silicone hybrid plug in your hole! This weighted plug is heavier than most plugs and its nickel free alloy is perfect for those with a sensitivity to nickel. The heavy metal plug is great for temperature play: heat it up or cool it down to add an extra dimension to your anal play session. The silicone base makes this comfortable enough for long term wear and adds a smooth sensation in between your cheeks. The silicone is phthalate free, non porous and body safe. Materials: Nickel free aluminum alloy butt plug, body safe silicone anchor base. Measurements overall length 4.5 inches, insertable length 3.5 inches, widest diameter 1.6 inch.