This is for the ninja ultima plus (model BL830) blender. The spout broke off mine so i designed one to fit. The first one i made lasted about 4 months of at least once a weekend of used. I always put it in the dishwasher afterwards too. I'm not sure why it broke but I just printed a new one and that has been going for 6 months.
To install this, put one peg in the slot and twist the other into place. It's very tight and requires a bit of forcing, but it works. I had a lot of failed designes but never broke one installing them. It will click into place just as the factory one did.