Tube Compatibility: ONLY for 1-1/2″ (38mm) EXTRUDED aluminum tubes (NOT for round tubes / other sizes) 2. The strong DC tubular motor handles heavy and wide window shades – up to 12 lbs. This 24V DC tubular motor kit works with your current 1.5″ (38mm) extruded aluminum roller shades – no need to buy new blinds.