6.4mm sight will raise point of impact on USP full size pistols approximately 4 inches at 25 yards.

6.4mm sight will lower point of impact on USP compact approximately 2 inches at 25 yards. 

Fits:

• USP9
• USP40
• USP45
• USPC9
• USPC40
• USPC45

Does NOT fit USP Expert/Elite