The TV Series features an injection-molded vinyl tapered design that can be used as a cap or a plug. Using an a-80 Shore durometer (hardness) vinyl, these caps resist tearing, cracking, splitting and shredding. Highly flexible, they enable snug fits even with smaller dimensions and irregular shapes. Easy installation and removal.:: a: 1.324, b: 1.460, C: 1.184, D: 1.320, E: 0.940, F: 1.68.