It is not the normal B454 or B454-E, it is B454-V, the tunning slide of second valve is different.
On the B454-V, you can change easily between Gb/D, G/Eb and Blair Bollinger's brand of tuning (designated "BB") without costly conversions.
The "V" means versatile, because the B454-V is the most versatile bass trombone on the market.