... .4mm 4. Option Color: NI CR CS BK BS BN GD This item BK-1 is in high quality and reasonable price ... them. Option Color: NI (nickel), CR (chrome), CS (chrome satin), BK (black), BS (black satin), GD (gold), BN (black nickel),. We ... for inspection if in stock... Tune-o-Matic Bridges &Tailpieces BK-1