Tom Of Finland 3 Piece Cock Ring Set Silicone. This 3 piece silicone cock ring set has triple the size options, with a premium material for longer lasting erection support. The smooth silicone is rigid yet flexible, with a matte finish and raised Tom of Finland logo on the outside. Comes in 3 graduated sizes, which you can wear alone or combine for maximum erection enhancement. Measurements rings 1.5 inches, 1.75 inches, and 2 inches in diameter. Material Silicone. Color Black.