With my eyes needing bigger and bigger print and the shaking in my hands I have a hard time filling my needles. This clear plastic guide allows me to magnify the print on my needle so my dosage is more accurate. The guide makes sure that the needle does not get bent while filling it. The insulin bottle also snaps onto the guide making the whole thing easy to hold.
I had one for several years (15 yrs) that my Wife bought for me for a Birthday present. It finally bit the dust when the glue dried up that holds the two parts of it together. So I purchased a new one!
Jan B