Brass Bibcock ndi mtundu wa valavu ya mpira wamkuwa, yopangidwa ndi mkuwa wonyengedwa komanso wogwiritsidwa ntchito ndi chogwirira, chomwe chimatchedwanso matepi am'munda wamkuwa, omwe amagwiritsidwa ntchito kwambiri popanga mipope, kutenthetsa, ndi mapaipi.