ISO 5415:2007 specifies the dimensions of reduction sleeves with 7/24 external taper No. 30-40-45-50 and 60 and Morse internal taper No. 1 to 6 (Morse taper No. 4, 5 and 6 being either with positive drive or without positive drive).
These sleeves permit driving of tools with Morse taper shanks with tapped holes with the aid of an internal screw. The form of this screw and its fixation in the sleeve are left to the manufacturer's discretion.
7/24 tapers are in accordance with ISO 297. Morse tapers are in accordance with ISO 296 and ISO 5413.