The piece that mounts the nozzle to the duster on my Reesibi R5 cordless duster broke, so I measured this out with some calipers and made it in Tinkercad. Print at whatever layer size you want (photo is 0.28mm on an Ender 3 Pro), the size is such that it's almost all wall as printed. Once printed, use elbow grease and squeeze it onto the duster on the big end and the nozzle on the little end. It doesn't do the swivel thing that the original just as an fyi.