I've made the ultimate converter lung for cosplay, but did I use too much silicone? The fine lines are blurred, so I'm lowering the price. Lungs made of hard materials restrict movement and can damage suits. For example, try putting a cutting board or phone book in your chest and bending forward or backward. You'll find it's quite difficult to move. This is the ultimate converter lung made of urethane rubber sponge, cotton, silicone, and felt. It's quite popular locally. Sew the edge of the lung, about 5mm in, to your suit. If you can sew a rag, you'll be fine. Lung size (one side): approximately 41cm (length) / 23cm (width) / 5cm (thickness). Currently, it has a glossy finish, but to make it matte, sprinkle baby powder and wipe it off with a wet towel. Current condition.