 From its introduction, the Detective Special used Colt's ‘Positive Safety Lock’ (hammer block), first featured on the Police Positive; the mechanism interposes a bar between hammer and frame until the trigger is pulled, preventing accidental discharge if the hammer is struck (e.g., if a dropped gun falls onto its hammer) with the trigger forward.First and early Second Series Detective Specials are becoming highly sought after by collectors, particularly if they are in prime condition and still have the famous Colt "Royal Blue" finish.The Detective Special was initially available in both bright blued and nickel finishes; a stainless steel finish replaced the nickeled option during the Fourth Series.