Things I liked: Size is just right for use while wearing gloves--about the size of a long highlighter pen. Works as intended for breech-loading spring air rifles, like my Benji Trail NP. Perfect for convenience of loading when pellet tins are a problem.
Things I would have changed: A bit more positive locking of the slider on the Pellet Pen would be nice. I worry that the slider part will pop off and get lost at times. A loop integrated into the top to allow the attachment of a lanyard for hanging the Pellet Pen around the neck would make this nifty gadget even better.
What others should know: Tip: Wrap a rubber band around the loaded Pellet Pen (above the slider) can help prevent the slider from backing off too far. Still trying to figure out a way to attach a lanyard to it that still allows reloading of it conveniently.