The 38-Special series has been designed and manufactured with the same proven, packed bed design, proper carbon for the job and solid steel shell as the Original Can-Filter. With the exception of the carbon bed (wall) thickness the 38-Special is identical to the Original Can-Filter. The Original Can-Filter has a 2.5 inch carbon bed thickness. The 38-Special has a 2" carbon bed thickness. The 38-Special provides superior performance with higher air flow ratings, less weight, cheaper price and an effective contact time of .08 seconds in contact compared to competing brands.